The canon 400D is a really good camera, it was the first DSLR that i bought.
The battery grips are so expensive i buy none branded versions as i do think they are worth while. I have got one for the 400D but not for the 5D yet.
Yeah the L lenses are not cheap at all but i do like the 100-400 L IS USM i tend to use that most of the time.
(hope you don't mind i though it would be best to move your reply to its own thread)