This has never been a risk before, but it's now possible to buy too much digital camera. How? It's all a matter of megapixels, short for "millions of picture elements," the standard metric for the sharpness of a digicam's photos.
Three megapixels is the effective minimum for photos that will look good in most printouts. If you think you're going to get a lot of 8-by-10 blowouts, four or five is the minimum. But think carefully about going beyond that; seven megapixels won't make your 4-by-6 prints any sharper, but each picture will take up a lot more space on your camera's memory card and your computer's hard drive.
Speaking of memory cards, remember that the starter-size one included with your camera will never hold more than a day or two of shots. You need to budget for an extra memory card right when you buy the camera. How much you'll need to budget depends on what kind of card format the camera uses. CompactFlash is the cheapest overall, and one of the most popular as well. SD Cards are only slightly costlier but much smaller -- they've become a standard format in handheld organizers and many MP3 players. SD Card is the closest thing to a universal memory card we have right now.
The other two types of card, Sony's Memory Stick and the xD-Picture Card that Fuji and Olympus use, cost too much for what they do. Ignore cameras that use these cards unless you can get an outstanding deal on them -- you'll wind up paying later on.
How much card? Figure 256 megabytes if you have a 3-MP camera, 512 if you have a 5-MP camera.
With resolution out of the way, you can consider the size of the camera itself. Buy the smallest model you can afford -- the beauty of these things is that they free you to take more pictures in more places, without having to load and develop film. So why let a too-big model get in the way?
Then again, if you travel a lot, you'll be happier with a slightly bulkier camera that takes standard AA or AAA batteries instead of expensive, odd-shaped ones. (Buy a set of rechargeables and save disposable batteries for emergency use.)
Last, if you are a photo enthusiast -- if one of the first thoughts in your mind as you frame the photo is "what's a good f/stop for this?" -- think about a digital SLR. These models are as hefty as their 35mm film counterparts, but they also deliver unmatched control and extremely high picture quality. They are also generally free of "shutter lag," the brief delay between you pressing the button on a digicam and the picture being taken. (Among smaller cameras, two Kyocera Finecam models use special circuitry to minimize this delay.)
-- Rob Pegoraro
Recommended in earlier reviews: Three to four megapixels: Casio Exilim EX-Z40 ($270), Kyocera Finecam SL400R ($280) and Finecam M410R ($330), Pentax Optio S40 ($220).
Five megapixels and up: Canon PowerShot S70 ($450), Kodak EasyShare DX7590 ($450), Pentax Optio 750Z ($500).
Digital SLRs: Canon Digital Rebel ($880), Nikon D-70 ($1,000, lens not included)