I would definetly recommened for your sub to look into any of the Rel subs. They are my personal fav, i am looking at a t-3 for my next upgrade. But they are very good subs, and they sepecialize in music. They have a seperate LFE connection, and a music connection that requires a different cable that comes with the sub. But it connects to the sub and the other end connection the the L & R speaker teminals, this way it when playing music it can just blend it with your speakers.
Honestly about the 7.1, i would just conncentrate on a 5.1 to start. 2 less speakers to buy at the start, really donesnt make that big of different (espicially if the room doesnt really allow it). Highly reccomend looking into any Pioneer, especially the Elite brand if you can, very good recievers and top notch quality.