Hey, I have a 12'x10' room with the 4Ts, 4Bs, 5C... and it could easily fill a larger room with more than enough sound. The towers are an excellent choice for music/games especially, plus cost about the same after stands for the bookshelves. Since you said you will probably turn it to 2.1 for the music I would definitely go with the towers. When I turn it to stereo & sit in the sweet spot I still swear the others speakers are all on.

As for a receiver, everyone has their own preferences, after doing alot of reading I went with an Onkyo 806 (although 606 would have been sufficient as well), but others will recommend Yamaha, Marantz, etc.