+1 on the Infinity Primus speakers, that is a fantastic deal. When you go for the center channel, try to get the Primus c351 over the c251. Alternatively you could simply use another p163 as a center, that would be cheaper. Hell, at the p163's current price, you could easily swing a 7 channel set. If you need a good mount, the best affordable bookshelf speaker mount is the AM40 Pinpoint side-clamping mount, you can get those for $60 a pair. If you aren't in a rush for the subwoofer, Outlaw ought to have a sale on their
LFM-1 Plus sometime this holiday season, those sales typically go for $500 shipped, and is a true 20 hz sub, some seriously deep bass.