Upgrading my camera

[Ballyn]

Hey Everyone!

I have been using my Canon Rebel XTi for about 4 years or so now...And my freelancing is actually taking off quite nicely lately. I'm doing a lot of portraiture and weddings (and of course my own art-sy stuff for my own pleasure) and I am feeling like maybe its time to upgrade...I have been looking at the Canon 50D. I borrowed my brother's 30D for a weekend and wasn't very impressed. When do you feel it necessary to upgrade? And when do you feel it necessary to upgrade to a full frame? I have invested in a lot of lenses for my XTi...and hate the thought of having to go full frame and start over with new lenses.

Thanks guys!