Speaker Suggestion for teenage pre-stereophile

I started off with an HK and JBL setup that I really enjoy for music. However, I've realized that I listen to music for hours upon hours a day, and hardly ever even get to use the multi-channel stuff. I've decided to get an integrated amp (probably NAD) and single cd player setup for my room-my question is what sort of speakers would work well for a 16 year old who only wants to spend 600 or so on the pair. Sadly, bussing tables will not buy nautilus' or krells! I listen to a very wide range of stuff; each day usually has neil young, cat stevens, the beatles, and other timeless greats....but also newer underground hip-hop (mos def, talib kweli, the roots). The room these would be used in is fairly small (unsure on exact sizes...but maybe 25x15???). I'll consider monitors or towers, but asthetics are important haha. Sorry, I know this isn't any easy question to answer, but any starting point for speakers would be greatly appreciated. Everytime I think I've decided on a set of speakers, another set steals my affection!