Unless you've recently emerged from a coma, you know the consumer versions of Microsoft's new Vista operating system ship Tuesday. Over the next few weeks, many people will try to convince you to move to Windows Vista, from design friends to product and software makers.

This column is not a review of Windows Vista. I'm not here to tell you about Vista or what's wrong with it.

This article is for those of you who are about to download or purchase Windows Vista and install it on a PC. I'm here to talk you out of it. Just say no to Windows Vista -- for now. Here's why.

1. Vista is incomplete

Microsoft is already planning its first service pack and seeking input from users on what to include. Vista probably won't be truly ready for prime time until that first service pack version, possibly later this year.

The hardware and software companies that make compatible products for Vista aren't all ready for the new OS. Many of those companies are scrambling to complete Vista drivers and updates. Most importantly, not all video and sound card companies are ready.

Audio and peripheral maker Creative publishes a list detailing the status of drivers for each of its many products. Most of their Sound Blaster Internal products already have Vista drivers available. Two of them have only a "beta 2" version of the drivers. Three of their older products say "No Development Planned." Most of their cameras and other peripherals have no Vista-specific drivers available.

On the Advanced Micro Devices site, you can find information about Vista readiness of ATI graphics cards (AMD and ATI merged last year). Most are supported by a Catalyst Vista Software Driver, which is "beta," and are plagued by a long list of published "known issues." It also comes with the following warning: "ATI does NOT recommend installing these drivers in systems used for mission critical operations or where productivity of any kind is a concern."

These two companies are on the leading edge of supporting Vista. Their partial readiness for Vista is symptomatic for the larger companies. Many smaller peripheral makers simply have no Vista support at all.

At least OEMs, Alienware and Polywell, are aggressively pushing XP over Vista, because both say graphics and other drivers for Vista aren't quite ready for prime time.

Software, such as the security suites you may have already paid for, may not run on Vista, and some require updates that aren't ready yet.

Trend Micro, Panda, CA and Symantec all have announced that they'll ship updated suites on Tuesday -- just in time for the consumer availability of Vista.

Microsoft claims McAfee will support Vista, but hasn't said when. The company itself has not announced Vista support. And some, but not all, ZoneAlarm products will support Vista by next week. The smaller the company, the longer it will generally take for them to support Vista.

Gaming on Vista -- and Vista's DirectX 10 graphics support -- is awesome for gamers. But that's something you'll be able to fully take advantage of only later. The full gaming potential of DirectX 10 requires three elements -- an operating system, supporting graphics hardware and supporting games. The operating system is ready, the graphics hardware is partly ready, and the games are nowhere. Eventually, Vista will be the ultimate PC gaming platform. But there's simply no reason for gamers to rush out and buy Vista next week.

2. Vista is expensive

Microsoft offers three versions of Vista to home users -- Home Basic, Home Premium and Ultimate. You can buy any of these in the upgrade version with a discount, or the stand-alone version without the discount.

The cheapest way for current Windows XP users to get a legal copy of Vista is to buy the upgrade version of Home Basic. But you don't want the cheapest version.

First, the upgrade version will require you to keep your Windows XP CD for years. You do have a Windows XP CD handy, don't you? Second, Home Basic just won't cut it for most people. It lacks the Aero UI and Media Center capabilities. Plus, you can't connect Xbox peripherals to Home Basic. For many, including yours truly, those are the three best reasons to upgrade to Vista in the first place.

Home Premium is roughly equivalent to Windows XP Home. It's for nontechnical, nonpower users who use their system for lightweight, personal use only. But if you're the kind of person who currently runs Windows XP Pro at home you'll be happiest with Windows Vista Ultimate. It's got all the fun and goodies of Home Premium, plus the power-user features in the business version of Vista.

Are you sitting down? The full version of Windows Vista Ultimate costs $399 in the US. If you have an XP CD, and don't mind the hassle, the upgrade version of Vista Ultimate costs $259. Ouch!

(If you buy the Ultimate Edition, you'll be able to buy additional copies of Vista Home Premium at a cost of $49.99. For technical users, the ideal scenario for many will be Ultimate for you and Home Premium for the spouse and kids.)

The cheapest Vista is the copy that comes with a new PC because you get in on the reseller's steep discount.

3. Vista wants a new PC

To get full value from Vista, you're probably going to want to buy a new, Vista-optimized PC. Many of the benefits of Vista require hardware your current PC doesn't have. "ReadyBoost" and "ReadyDrive," for example, require special hybrid or flash drives. Aero looks awesome, but only if your graphics card supports Pixel Shader 2.0. You can record high-definition cable TV, but only with a tuner card designed to take advantage of that Vista feature. You can enjoy DirectX 10 games, but only with a compatible video card.

Vista's new indexed searching is great, but you'll need extra hard disk space for the index -- and extra storage for the operating system itself. Don't even think about running Vista on a system with less than 1GB of RAM; 2GB is reasonable and 4GB is the sweet spot. And if you want to really enjoy the Aero eye candy, you'll want a 20-inch or larger flat-panel LCD display.

Sure, you can buy Vista and install it on an old PC. But that's like subscribing to HD cable, but not buying an HD TV. You're paying for the HD experience but not actually experiencing it.

4. Vista is time-consuming

Installing any new operating system is time-consuming. You have to configure everything, load your data, install your applications and get your peripherals working. Then, in the case of Vista, you have to figure out where Microsoft buried all the options, menus and features and get used to the ubiquitous Search boxes. Anytime you want to do anything in Vista, it seems, the software asks, "Are you sure?" You'll want to figure out how to turn that off and customize Vista to get rid of all its annoying "user-friendly" hand-holding "features."

But buying Vista now, and installing it on old hardware, adds additional, time-consuming tasks -- possibly an additional day or two. Why? Chances are, you'll have to hunt down, install and troubleshoot new drivers for your old peripherals and system components.

You may have heard about Windows Easy Transfer, which moves files and settings from XP to Vista. But don't get too excited about this. It works only after you've re-installed all your applications; it doesn't actually move installed applications, just settings and data.

By waiting, and getting Vista on your next PC, you'll save yourself the pain and hassle of trying to retrofit your old PC with the new operating system.

5. Windows XP isn't obsolete

Vista adds new benefits and, in the long run, will make computing easier, faster and a lot more fun. But it doesn't really "solve" any existing problem. Windows XP -- after years of service patches and strong, industrywide support -- is a solid, well-understood and highly functional operating system. And it will continue to be well supported. Microsoft itself has committed to at least seven more years of XP support, and even plans a Service Pack 3 next year.

Gartner says that by the end of the year, XP will be installed on 77.1 percent of all PCs worldwide, and Vista on just 12.3 percent. That means the industry will make sure their new products still work great on XP.

6. Vista may be the best reason yet to buy a Mac

That's right. I said it.

Years ago, "switching" from Windows to a Mac was nearly impossible for most people. We relied entirely on desktop applications, many of which had no equivalents on the Mac platform. Today, so much of what we do is online -- and Apple has done such a good job of making the transition easier -- that leaving Windows and moving to a Mac is perfectly doable for most people. It's a real choice now, and mostly a matter of preference.

With Windows Vista as the default operating system on any new system you buy, it makes sense to consider moving to a Mac. After all, Vista will force you to learn a new operating system anyway, and -- in the short term -- one less supported than XP. In either case, you'll be using a 3-D interface, widgets and other goodies.

Apple will start selling the next version of OS X, code-named Leopard, this spring. The details of this operating system are secret, but it's likely that it will be spectacular. All may be revealed as soon as next month. If you're going to buy a new PC this spring, you might as well check out Leopard before making your choice.

Under what circumstances should you "switch" to a Mac? Apple fans will tell you that the answer is obvious: If you want your system to crash less, run with fewer hassles and fewer security breaches, then buy a Mac. But that's the Mac user's world view.

If you're looking to make that decision from the PC users world view, here's a more practical checklist.

Consider switching to a Mac if:

-- You're not into PC gaming.

-- You don't have any Windows-only applications you'd still like to run without emulation.

-- You don't have major PC hardware investment -- such as expensive flat-screen LCD displays -- to take advantage of.

-- You don't have non-Mac applications that are required by your employer for working at home.

Most Windows users won't make that choice, however. For most of us, resistance is futile -- and unnecessary and undesirable. Windows Vista is a truly great version of Windows with enormous benefits and will be a lot of fun to use.

But before you upgrade the hard way -- and on the wrong hardware and before the industry is fully ready to support it -- take a moment and consider: What's the rush?