QUOTE(pogs16a2 @ Oct 9 2007, 06:22 PM) [snapback]726533[/snapback]
Yes you could overclock to e6750 speeds, or you could overclock a E6750 to 3.4+ speeds.... and yes if your going to be playing stuff like Crysis then I'd recommend a 8800, plus you won't have to upgrade for quite a while.
Never compare an OC to a stock speed, sort of like apples to oranges, they both can OC

While his reasoning isn't correct, the e6750 is still a better choice over the e6550.
e6550=7x333=2333mhz -$175
e6750=8x333=2666mhz -$200
e6850=9x333=2999mhz -$280
q6600=9x266=2400mhz -$280
You'll be severely limited with that low multiplier, you'll hit a wall much faster than the higher multi'ed siblings. Personally, I'd save up a few dollars and go for the e6850, or q6600, which have the high multiplier, funny thing is that the quad core q6600 is the same price as the e6850. Granted, the quad doesn't OC as far as the e6850, but it isn't that far behind. (But make sure to get the G0 revision of the q6600, which is the same revision as the e6x50s, runs cooler, and OCs much farther.)
But I'd highly recommend the e6750 over the e6550 if you plan on OCing at all. You're guaranteed 3.4ghz on the dual core G0s (excluding the e6550), at least 3.2 with the quad, with decent parts and cooling.
The graphics card is up to you, but if you play the "waiting game" then you'll never experience the full power of your rig. Technology changes way to fast, might as well get used to it.