Well, I have a 400D. I have recently upgraded to a 40D, purely for the bigger grip, the images they both produce are very similar.

The 400D is a great camera, it has some really nice features like sensor cleaning and it feels well made. If you can get a kit with the new 18-55mm IS lens it is a great improvement over the standard kit lens (18-55 no IS), one came with my 40D and I had planned to sell it, but I think I'm going to keep it as it seems sharper than other lenses I have that cover that range.

I have to make the same decision as you a few years ago, Nikon or Canon? In the end I went down to Jessops and held each camera in my hand and went with the one that felt better. Maybe not the best way to make a choice but the cameras are so close these days it was the only way I could stop my self buying both

Cheers

Cris.