Under $300 with a digital input, I'd consider:
HK 3490
Pioneer VSX-918V
Onkyo TX-SR576 or 506 (and check acceessories4less and shoponkyo for authorized refurbs)
Denon AVR-589
Yamaha RX-V363, 463, 563
Yeah, you don't need HT processing/multichannel amps, but as many have said before, the extra features in HT receivers like bass management for your sub, speaker / sub distance for phase control, and, in the case of the Denon, Audyssey room EQ, improve your 2 channel listening as well (and add to future versatility and resale value).