Ok if you must get the all-in-one kit...
I set up a kit for a friend a few weeks ago. They didn't care to consider building the system up over time, or any of the other good pieces of advice from the other posters. So we went to BB, CC, GG, and all the crappy choices in between. Apart from open-box buys (which he really didn't want), there was nothing decent in his price range. So I suggested the following: buy a kit with crappy speakers but with a solid non-proprietary receiver. Sounds stupid, but if you think about it, he got his surround sound system the same day (well actually it was late in the evening), he saved a ton of money, and he was happy. We set it up the next day.
Well, I came over last weekend because the front speakers were clipping when he turns the volume way up (duh!), and he was really miffed about that. But because we bought a good receiver, we could hook up any type of speaker to the standard binding posts. So I lent him an old pair of junkers I still had in the garage, and he's now happy as clam, so much so that I received a check for my old speakers today (and I don't have to go through the trouble of selling them on ebay).
The moral is, make sure the heart of the system is solid.