Like Gonk, I'm a very satisfied Paradigm owner. They can be a bit power hungry, but I find that the 7125 does an ample job of keeping my speakers from "wanting more". If budget is a concern I would look into the Monitor Series. Though not as sexy in design as some other manufacturers, the bang for the buck is impressive.

As far as the room goes I'll be redundant in saying that a perfectly square room can produce pretty unsatisfying standing waves. Utilize the room calibration equipment that accompanies the 990. That should help some. Otherwise, I would insulate all walls with the fiberglass and research acoustical treatments. Hanging curtains and acoustical boards randomly throughout the room can actually make it sound worse, so do your reserach. Find out where your reflection points are consider use of bass traps if they fit your budget.

Try this link.

http://www.myhometheater.homestead.com/Acoustics.html

I used it when I was planning my theater room and it helped. Bear in mind there is no substitute for a qualified trained professional. They may cost more, but if you're serious about wanting the best sound from your room it may prove worth the time and money. Good luck to you and welcome to the fold!