To the above poster: They're both eVGA products. EVGA recently released an overclocked version of the 6800gs.
To the original poster: I looked at the 6800gs for $169 after rebate. This is at newegg, correct? If you look closer at the rebate, you actually have to buy the 6800gs AND an EVGA Intel motherboard. So, unless you're planning on buying the mobo too, the $169 doesn't apply to you.
I'm sure you'll want to clarify this for yourself, so here's the link:
But for $189, the GS is still a great card. I just bought one myself.