If the only video you shoot is clips of your dog for YouTube, most any camcorder will do. But if you're recording your child's first steps or daughter's wedding, you want some assurance that it will still be viewable in 20 or 30 years, when you'll get the most pleasure out of watching it.

While today's digital video formats will undoubtedly be obsolete by then, you can choose a reasonably future-proof video camera by following three key guidelines:

-- Buy the best image quality you can afford
-- Capture in a widely supported format
-- Use a long-term storage medium

No single camcorder we've tested performs ideally in all of these criteria, but keeping these demands in mind helps narrow the field to a manageable number of cameras.

To get the highest image quality (and full-quality playback on that spanking-new HDTV you bought) you should be thinking HD. There are two main high-definition video formats in consumer camcorders: HDV, which came out in 2004 and uses the same kind of MiniDV tape cassettes as the original (and hugely successful) standard-def DV format; and AVCHD (Advanced Video Codec High Definition), a still-maturing format that first appeared in mid-2006 and can be recorded to DVD, hard disk, or flash memory.

AVCHD vs. HDV

AVCHD has several major advantages over HDV: a more efficient compression algorithm that uses less space per minute of video (an important consideration for long-term storage), drag-and-drop file transfers from camera to computer that are up to ten times faster than with HDV, and random-access media that beats the fast forwarding and rewinding of tape hands-down. Since AVCHD uses the same MPEG-4 compression as Blu-ray, you can also play AVCHD discs in Blu-ray players without re-encoding them, which is a real convenience. It is poised to become the dominant consumer video format. But HDV is not dead yet--in fact, it may still be your best bet.

HDV remains a good choice for three reasons. First, the best consumer HDV camcorders still have better image quality than the best AVCHD models (although AVCHD is catching up fast). And pro-level HDV camcorders are staples of TV production, whereas professional AVCHD cameras are just emerging.

Second, despite its awkward and time-consuming camera-to-PC transfer mechanism, the MiniDV tape used by HDV is its own handy long-term storage medium--you can just toss it in a drawer after you're done editing. A 60-minute tape costs only US$3 or so. By contrast, AVCHD requires burning to optical disc for shelf storage, or dedicating hard drive space year after year. A 1-terabyte hard drive will hold about 125 hours of AVCHD video at the current top bit rate of 17 megabits per second (mbps), but you'll need to double that to back it up. Tapes are also useful on vacations, when it might be difficult or impossible to offload video from your hard disk or memory card.

Third--and a good reason to hold off on buying an AVCHD camcorder if you can--is the AVCHD format's immaturity. Most consumer video software is only just starting to handle AVCHD, and even then it may not take full advantage of your specific camera and its many shooting modes. For example, a program may handle 1440 by 1080 AVCHD at 60 interlaced frames per second (60i), but not the newer 1920x1080 or 24p (progressive scan) variations.

To use AVCHD in the current version of Windows Movie Maker, you'll need to convert it first, thereby losing image quality. Furthermore, AVCHD has not yet reached its maximum quality potential. While the spec allows for bit rates up to 24 mbps, only a handful of cameras even support 15-17 mbps. And no consumer AVCHD camcorders yet offer the true 1080p support that will get the most out of your HDTV.

All that should change over the next year or two, as AVCHD camcorders finally hit their maximum possible bit and frame rates, and as software support becomes more reliable. Prices should also continue to come down.

Camcorders: The Current State of the Art

If you must buy now, here's what to look for in a future-proof consumer HD camcorder.

For HDV: Here, the choices are relatively simple.

Since all HDV camcorders record at the same resolutions and bit rates to MiniDV tape, the features to look for are the things that increase picture quality in any camcorder, such as a good lens with a long optical zoom, a big image sensor (CCD), image stabilization, and great low-light performance. See this helpful Digital Camcorder Buying Guide for more on these features.

The Canon Vixia HV30 ($999) and the Sony HDR-HC9 ($1099), both introduced this spring, currently top most reviewers' HDV quality charts. Both cameras have 10X optical zoom and HDMI ports for direct hookup and playback on your HDTV. If you don't plan to edit your home movies, the video never needs to touch your PC at all, sidestepping the downsides of tape.

For AVCHD: This is where things really get complicated, due to the wide range of recording media and capacities in AVCHD camcorders. Sony alone has ten models: four hard disk-based, five DVD-based, and one with Memory Stick-only recording. But the models of interest are the full HD 1920x1080 cameras with a maximum 16 mbps bit rate, which narrows things down to four: the hard disk-based HDR-SR10 (40GB), SR10D (120GB), SR11 (60GB) and SR12 (120GB). The HDR-SR11 ($1200) and SR12 ($1400) have better image sensors and LCDs, and higher still image resolution (10MP) than the SR10/10D (4MP). The 120GB drive holds about 15 hours of video at maximum quality, and all can be expanded with Memory Stick Pro flash cards.

Canon and Panasonic each have two models of comparable quality. Canon offers the Vixia HF10 ($1100) and HF100 ($900). Both are flash-based, and record at up to 1920x1080 and 17 mbps. The HF100 has a slot for SDHC cards that hold one hour of maximum quality video per 8GB. The HF10 has 16GB of built-in solid-state memory as well as the SDHC slot. Panasonic's entries are the HDC-SD9 ($800) and HDC-HS9 ($1000). Like the Canon HF100, the flash-based HDC-SD9 offers 1920x1080/17 mbps recording and an SDHC card slot that runs 8GB per hour. The HS9 basically adds a 60GB hard disk to the SD9, for about 7.5 hours of top-quality recording.

Note that while all three vendors offer DVD-based AVCHD camcorders, none are capable of the maximum bit rates of the flash and hard-disk models, so for long-term storage, you'll need to copy the video to another drive or use your PC's DVD or Blu-ray recorder to archive it.

The HDTV Colour Connection: xvYCC

The Panasonic and Sony camcorders mentioned here (both AVCHD and HDV) support the expanded colour range of the xvYCC standard, which promises an amazing 1.8 times more reds, greens and blues than standard sRGB colour. With xvYCC, colours are more accurate and have smoother gradations.

xvYCC can be displayed by many new HDTVs from the two vendors, and is part of the HDMI 1.3 specification. Panasonic brands it as "Digital Cinema Color," while Sony calls it "x.v.Color." Since xvYCC is a standard, theoretically camcorders and TVs from various vendors should be interoperable, but both companies recommend sticking with one brand for both HD camcorder and HDTV for guaranteed results. If you don't have an xvYCC-capable HDTV yet, it doesn't hurt to record in this format for future use. The extra color information will simply be discarded on its way to your TV.

Note that xvYCC is related to, but not the same as, "Deep Color," another HDTV technology that refers to higher bit depth. Both increase the number of colours available, but only xvYCC is currently available in consumer camcorders.