Would a Dual Core still be enough??

I am a gamer and need to build a new system. I am first time builder and would like to pretty much run any game.
Would it be wise to build using a dual core? Or should I just go ahead and do the quad>?
Also, I am unsure if it is possible but is their a MOBO that supports both dual and quad that I could maybe use
for upgrading to quad at a later time?

yeah, definitely need more details. Depending on the game, a highly clocked dual core like an E8600 would probably keep up pretty well with a brand new core i5 750 when looking at fps alone. For AMD dual cores, they tend to not clock as high and wouldn't be as good candidates. The problem I see with intel dual cores is that their socket, LGA 775, is on the tail end of its life cycle, new products are not going to be made for it. When core i3's become available next year, core 2 duo's will be regarded as pentium 4s are today. Supposedly the i3's are that much better at doing what core 2 duo's do now.