My standard answer: rent. In your case, my suggestion is to rent a lot.
You need at least two cameras, You need two ways to cover the wide end, perhaps 17-55/2.8 and 24/1.4, or 17-55/2.8 and 24-70/2.8. If one lens dies/falls/goes swimming in paint, you need another way to get the shot. You need something long, perhaps the 85/1.8 as others have suggested, maybe also a 135/2 or a 70-200/2.8 of some form.
You need to find out if you can use flash inside the venue, in writing. If you can use flash, you need to become an expert at off-camera flash, and train an assistant to move your lights with simple signals, so you should buy whatever you're going to use NOW and start learning FAST. If you can't use flash inside, you need to rethink all of your camera/lens choices. I'd be thinking 2-3 5D bodies, the 24/1.4, 35/1.4, 85/1.2, and 135/2 perhaps.
My fiance and I shot a wedding two weeks ago. We don't do weddings, and we "did it for a friend". Since we weren't getting paid, she decided that we weren't going to rent anything, and just work with what we had. I shot with a 1D3 and 24-105, and 7D with 70-200/2.8IS. She shot with 40D and 16-35/2.8, and 7D and 28-135 kit lens, with a 580EXII on each. I used two 580EXIIs remote with PW Flex units. She wanted something a little better on the long end, but didn't seem to feel too cramped without. As the sun went down, shooting at the reception became increasingly difficult, and after the staff turned out the "christmas lights" criss-crossing the pavillion, it became essentially impossible to AF with the 7D/70-200.
When we do jobs (not weddings) "for pay", our standard lens lineup is 16-35/2.8, 24-70/2.8, and 70-200/2.8IS for me, 10-22EFS, 24-105/4IS, and 70-200/4IS for her (she prefers lighter weight). If I had my druthers for this gig, I'd have rented at least our standard lens lineup, and possibly the 35/1.4 and 85/1.2.