Well I just found out that I won a sweepstakes for a intel core 2 quad 9300 from zipzoomfly. My current system already has the q6600 in it. So since I will have an additional CPU sitting around I am thinking about building another pc. My current machine is by far no means a gaming machine but since I do not play very intense games it suit my needs just fine. However I have wanted to build a machine for my living room to store music, videos, etc... So which core (q6600 vs q9300) should I use for my main system and which should I use for my "media center."
Well I already have the Q6600 and I just won the Q9300 for free so I will have them both. But I see what you are saying though... for OC q6600 and if not OC'ing the Q9300. I wont be doing any OC'ing I dont think because I have never done it and the machine that has the Q6600 wouldnt be able to tolerate OC'ing I dont think (its one of those HP media pc's).
The Q9300 at stock is just a bit faster than the Q6600 at stock. I doubt you'd notice the difference in real life, it's very small. The Q9300 has support for SSE4, which makes it better if you use software that supports it.
Use the 9300 in the media centre, the 45nm chip will run cooler and has the newer multimedia extensions (SSE4). The 6600 is an excellent overclocker so better for gaming (if overclocked) but will need better cooling and hance produce more noise.