I have a 350D, and I found the 50D not innovative enough to pay such an amount of money for it. The 7D really is on my wish list, as it adds so much. The key features to upgrade to the 7D (apart from higher resolution and less noise) are:
- Built-in speedlite master. This allows me to take my 580EX-II off-camera, giving me 33% more off-camera strobes (I also have two 430EX's).
- 100% view finder coverage.
- Built-in artificial horizon.