Zenith has some nice models in that price range. Panasonic, Samsung... Maybe even a lower end Sony? I'd tell you this: You can get a refurbed Onkyo 760 or 767 for around $300. Some B&M's have been doing clearances near that price as well. The Onkyo 760 has to be the best bang for the buck in...
Good HTIBs: Onkyo 760, 767, 770, 777 (I think these are the best bang for the buck. You can get the 60 series on clearance and refurbs for as low as $300. Really incredible sound for an HTIB. ) Sony 7700D Check the Yamaha line as well.