Which CPU should i choose?

At the moment I have been putting together a new computer and I am trying to decide which CPU would be better for gaming. I am choosing between a Intel Pentium Dual-Core E6300 Processor which is 2.8 GHZ or a Intel® Core™ 2 Duo E6300 which is 1.86 GHZ. Also, this is a little off-topic, but the graphics card that I am putting into the system says that it is recommended that I should have either Pentium 4, Celeron, or Duo inside the system. If i did not have any of these in there would the video card not work properly?

buy whichever cpu is more expensive, the more expensive one is better, where i used to work one of my co workers thaught the 3.2 ghz pentium d in his machine was better than the 2.2 ghz core 2 in mine, we ran some benches and what do u no, mine won, clock speed is not the most important factor anymore, or the upcomming phenom ii 965 would kick the bajeeses out of the i7 920