How good are the Sony str-dh500 sony str-dh800? I'm a complete noob and they look like great value. I mainly want Surround sound for a feeling of immersion within my PS3 and 360 games. I'll also be watching HD-DVDs and BluRay movies. I may start out with just two speakers and upgrade over time so the I'm not spending a fortune in one go. I think I'll be able get better speakers this way too.