8800 GTS 640mb - buy stock OC or not?

I can get an EVGA 8800 GTS 640MB SuperClocked for about $30 more than the basic version. Is it worth the extra $30?

How easy is it to bump up the clock on your own.

Any advantage to buying the BFG GeForce 8800 GTS OC2 instead? ($10 more than EVGA)

I know I can save a ton by getting the 320MB version, but I'm worried about future proofing as this card has to last me a few years. And I get the feeling that games are going to start asking for mim 512MB vram.

That's subjective and up to you, in the end.

The advantage of having a factory overclocked card is that it is already overclocked (Obviously), and under warranty while overclocked. The drawback is that it probably won't overclock much higher than that.

The advantage to a normal card is that you could potentially overclock to higher clocks than a factory overclocked card. The drawback is that, depending on the manufacturer, overclocking voids the warranty, and you could burn out your card if you aren't careful

So, really, its up to you. Research it more if you need, then make the choice being well-informed. Good luck!