If you have $1000 bucks, I'd get a set of B&Ws used. You can't go wrong with any of their models. I personally own DM602 S2s in the rear and sides with a set of B&O in the front (RL140). Should should be able to pick up a pair for $300 (x2) plus a B&w center for $250. You will have an amazing setup.
To reply to the "best brand". Great sounding speakers vary by ear and personality to a wide extent. If your going to spend "1000's" listen to them first. Not all speakers are great at everything. Some speakers are heavenly listening to music, but not quite as wonderful in a theater setting.