I love my new Canon 350D. It's the first SLR I've owned, and the pictures are automatically 10x better than my little Canon Elph S400. It's the only time in my life where spending money made me a better artist.
But inexpensive digital SLRs don't shoot a full 35mm frame. Instead they have smaller sensors. The 350D has a "1.6x crop factor", which basically means your pictures look OK but your lenses are more telephoto than you'd think. A 35mm lens acts like a 56mm lens. If you want a wide angle 28mm shot you have to buy a 17mm lens. Really wide angle lenses for these small sensor cameras are very dear.
Canon has tried to turn this liability into an advantage by selling "EF-S" lenses, special lenses that only work on small sensor cameras. They go deeper into the camera body, and in theory allow for cheaper / lighter lenses. All I know is they don't work on all cameras, just these small sensor ones.
And while right now most digital SLRs are small sensor, there's reason to think that Canon may soon switch to all full size sensors. The newly announced full sensor Canon 5D is a bellweather here. At $3300 it's a lot more than the $800 for a 350D, but a lot cheaper than the $7600 that the current cheapest full sensor camera costs. Folks seem to be excited by the 5D full frame. Wide angles that work like wide angles, better viewfinder, what's not to like?
All of this is a long-winded way of suggesting that EF-S lenses may not be such a good investment, that in four years you may not be able to buy a good camera that uses them. Which is sort of an awkward position for Canon. They've made some serious EF-S lenses, will they abandon their customers?