Hi there, and welcome.

My GF bought a 400D a few weeks ago and got quite a good deal on it. I suppose that one of the big differences between them is that the 450D has live view and the 400D doesn't. The 1000D is the latest thing so that might be worth a look too, or, there seem to be good deals about on the metal bodied 40D.

On the lens front don't forget that these Canon camera have a 1.6x "crop" factor so the zoom of any lens fitted is effectively multiplied by x1.6. A "standard" zoom in the 17-50mm type range may therefore be a good starting point. Tamron do a nice 17-50 (equivalent to 28-80mm) f2.8, Sigma do a 18-50 f2.8 and also a 17-70. Something like this will enable you to have a go at landscape and general use and they all focus quite close, but aren't true "macro."