It depends :-). If you are a bit of a technical nerd and want the-latest-and-greatest it is not so fun to buy a full frame camera now, since all of them are showing some age compared to the newest APS-C models. However, if you care more about making pictures buying a 5D now makes sense. And we don't really know when the next 5D comes out, and what price tag it will have. I would not be surprised if it slips into 2012...
Anyway, the big thing is the format, the shallower depth of field etc, the next model won't radically change how you make pictures. If you feel you need the format now, just buy.
And your 7D is a very nice complement to 5D.
I'm myself in about the same situation, however I'll wait to the next model, but that's since I need to save up money anyway, so I almost hope that it won't come until 2012...