My PS3 is totally silent no matter what. My 360 is pretty quiet when it plays DVDs or CDs. Games on the other hand......... Personally, if I were you and I had an HDTV, I'd go with the PS3. I'm a HD nut, though. If your priority is games, I say go with the 360.
Or, you could just buy a DVD player. They're about $15 bucks now!