With regards to the 7D vs 5D mark 2. It 5D definately has the edge on image quality for portraits and works better in low light, however the 7D is more than capable of taking excellent shots. It is not as great in low light, but it has an ultra fast multi shot burst and a fab option of focal points. I settled on the 7D as I like wildlife as well as people, so it was the best option for me. I have the 70-200 f4 L lense and the 24-105 f4L fab lenses but had I had the money I would have snapped up the 70-200 f2.8L especially for low light situations. the 24- 105 is on my camera for most things people based. As it is cropped sensor I am now saving for a wide angle lense as Ballyman said.
have a look at my flicker site to see what the 7D can do. But I am still learning so bear that in mind lol
Public liability is the one the hotels / venues will look for but i would also strongly recommend getting public indemnity for your own peace of mind like the previous posters have said camerainsurance.ie are very good. Id recommend camerainsurance.ie for great service and price.
A high quality camera lens is the key to taking good photographs. Most wedding photojournalists routinely use a variety of lenses to shoot. Choosing which lens to use while photographing a wedding, is obviously an extension of your own style. My two workhorse lens with which I photograph 90% of the wedding day, are the 24-70mm f2.8 and the 70-200mm f2.8.