I bought my 330xi from Autohaus and they were absolutely fantastic. Very accomodating and got the car as fast as possible, answered all my questions and found out promptly for things they didn't know 100%. Parts gave me a bunch of free stuff too and I get 10% off anything I buy there (less wheels, big ticket items, etc...). I dealt with Keyhan and would most certainly recommend him.
As for Town & Country which everyone seems to be raving about, read my post here to see what I have to say about them (before they moved location):
http://www.e90post.com/forums/showthread.php?t=27132 It's post #6