If you have money to flush away on a new computer every year or two, then go with the the e6850 as it will outperform the Q6600 in the short term. However, more and more games and applications will start to utilize quad core, making it much much much more future-proof and better for the long run, which is why I went with the Q6600 on my new computer. I bought the OEM version from ClubIT (b/c they can guarantee I'll get a G0); it cost me about $270.