I second the Nikon D40 (or D50)! I have a D40 and absolutely love it. The clarity and shutter speed are so much better than my old camera (Fuji FinePix E550). I think the D40 is the least expensive of Nikon's D-SLRs. It's a great starter SLR camera, with the ability to change out lenses once you learn more about it. The only thing I'm not a fan of is the auto-flash, but you can of course turn that off.
Good luck with your camera hunting!
1 yoyo loach, 2 polkadot loaches, 6 cherry barbs, 2 turquoise rainbows, 1 chinese algae eater, 2 harlequin rasboras; java fern, java moss, hornwort, Asian ambulia