I cannot recommend the 7D for wedding photog. Get a 6D or 5D Mark III. Well, get a 5D Mark III if you can afford it.
As long as the lighting isn't too bad, the 7D does just fine. It's a great second camera, and you might just need that extra reach. I've shot a few weddings with my 7D, no problem. I know an awesome professional photographer that shoots exclusively with a Rebel XSI. It takes a lot more than megapixels and ISO performance to make a great photo.
5D Mark III, 7D, EF 24-105mm f/4L IS USM, EF 50mm f/1.4, EF 70-300mm IS USM, EF-S 17-55mm IS USM, Redrock shoulder rig, matte box & follow focus, Rode Videomic, Zoom R16, Sure PG42, DSTE Pro BG-E11, Excella Neo D400 Studio Strobes, Excella Stardust 50, 580 EX II, lots of other fun stu