Medal of Honor is all but set to be a colossal flop. It doesn't look like it brings much new to the table at all, and it will be running up right in between Reach and COD: Black Ops, which Activision is really pushing to be as good as possible since Infinity Ward is now gone.
So I would go with COD, if you're not tired of the franchise already.
(I think that other new military shooter that got delayed, which I cannot remember by name, the one they were showing with move support, actually looks pretty good and I'm more interested in that that MoH.)
EDIT: And welcome to the forums.