Suggestions for a budget amp

Well, im thinking about upgrading my system (just started out and am still in high school so my budget is a major constraint). Basically im trying to build a sterio system that will last me until im out of college and have a "real" job. My current system includes NHT-SB3 speakers, Onkyo TX-8211 sterio reciever a sony CDP-CE275 cd changer, Furmann Q-2312 EQ, and blue-jeans cabling. Its my opinion that the Onkyo is what holds the system back the most at this point so im looking to replace it and fight the upgrade bug until i can afford it. I've looked at the Rotell RA-02 and the Nad C320Bee (the Nad is my favorite so far) but need more ideas (there HAVE to be more budget amps out there, right?). I also shopped around Yamaha's and Onkyo's sites, but their higher end stuff just adds more features, not much by the way of sound quality (from what i could tell by specs... may be wrong). Im looking for something that i can upgrade in stages down the line (i.e. unplugging the power amp section of a preamp and using a beefier seperate, or bi-amping... something like that). I dont need much power since ill be in dorm rooms or crowded appartments for the near future and even in my fair sized room now i rarely turn my 40 wpc Onkyo above 9:00 and its never been over 12:00. I listen to everything from Mozart to Metallica, except rap and pop. Even put in some country every now and then (I think its a law here in Texas ;-)
Thanks for your help,
-Dan-