Well, two steps actually, as I upgraded from a 400D to a 7D today!
I used the 400D for almost three years and over 20,000 photos and loved using it, but I felt like I reached its limits. I'm doing a lot of shooting in difficult circumstances these days (Airshows, racing, concerts) and the 400D couldn't give me the results I wanted. The 7D is a big step forwards, with 8 fps, 18 megapixel, ISO settings up to 12800 and a lot more goodies including live view and full HD (1080p) filming!
No photos yet because once I got home late this afternoon (150 mile drive through snow and rain) I still had to RTFM and charge the battery. For indoor shooting I also got me a new lens: A Tamron 17-50 XR Di F/2.8 with a B+W filter. Very good quality at half the price of the Canon EF-S 17-55 F/2.8 (Though that one does have IS).
Will be going to a museum tomorrow (With some other SOH folks) to test it!