Nick,
I just (February) purchased a Canon Digital Rebal 6.3M from E-bay. Came with stock 18-55mm lens. Ended up costing me $329.75 with shipping.
EXCELLENT CAMERA!!!
Many people are upgrading to the XTi right now, and selling their old 6.3M cameras.
The main thing is, it is a true SLR camera. The lens is what makes the SLR camera, not the amount of mega-pixels!!!
With a 6.3M picture, I can easily print any picture I take, up to just over 8.5" X 11", with no pixalation. True, if I wanted to print a POSTER, this wouldn't be a large enough mega-pixel camera... and the 10M cameras would be better. But... honestly, especially with a digital camera, what do you want it for??? For viewing pictures on your Computer. Graphics resolution on your monitor isn't much more than 96dpi... so even a 19" monitor doesn't even show a 8.5" X 11" picture without some good scrolling!
True, the 18-55mm lens isn't the best of lens... but now that I do own the digital camera, as I get more $$$, I can add the nicer lens to my camera, and take some very impressive pictures!
Also, being digital, unlike the old film cameras... you can take a quick 50 or 60 pictures of your tank, and instantly look at how they turned out on your computer! Learning how to use the camera in all its various modes is much easier because of that!
Just a thought for you, in your search for a camera.