The 550D looks like great bang for the buck at the moment, considering its basically the same sensor as the 7D; it's a bargain!
I thought about that when I bought my 7D. For video, I totally agree, at least from what I know about it.

For still, the 7D has a real prism and a claimed 99% (or was it 100%?) FOV and a HUGE viewfinder. I never thought that would make a big deal to me, but its so awesome I can't stand to use my 350D any more with its tiny, dim view finder. I don't know if I'll ever use another SLR without a solid prism.

On the other hand, by the time I get around to replacing the 7D, cameras might not even have flappy mirrors any more.