While I generally agree with the monitor-and-maybe-sub advice as a starting point, I'd recommend that you experiment with different types of speakers in your price range. Some tower speakers use small drivers and aren't really that large in volume, so they produce less bass than you might think (as well as less bass than the spec sheet says, but that's almost universally true).
Room size-how do I determine speaker size?
HI. I am moving soon (to a small house), with a living room of 12x12. How do I determine what size of sperkers will work in the room? Monitor, 2-way floorstanding, 3-way floorstanding? I was thinking that monitors may be a good choice, but I don't want to totally miss out on bass response. Is there a "rule-of-thumb" regarding room size and speaker size?