Like a number of other company's, Infinity make some world class speakers (Prelude MTS) right down to affordable bookshelfs.
I personally use an Infinity Alpha Sub/Sat system, 5.1, for my movies. this suits my budget and space (I live in a dorm like room right now, so space is tight.)
I find the 2-way satellites are quite good considering the price, and they utilise the CMMD midrange driver, and the soft dome tweeter isn't overly bright. Voices are very natural, especially compared to some other offerings around the same price from Boston and Tannoy
The sub isn't up to the quality of the sat's, and can exhibit a lack of real extension and punch in the lower range, but this is usually only evident in BIIIIIIIIG explosions....
Overall, I'm quite happy with them for now, especially in terms of bang for buck, which was what i was after in buying them. these only serve as movie/HT speakers now, as my B&W's perform music duties. Until I buy a M&K sub/sat setup around mid next year, I'm more than pleased with their performance...
Depending on what you want to spend, I think Infinity has a speaker to match all budgets... However, check other offerings like the 300/600 series from B&W or Q series from KEF... I'm sure there's other brands local to the US that fit around this area...
Hope this helps..