3331,
Why dont you try OCing your 6800 and see if you like it or not before deciding to sell it? Eventually they'll come out with a 7800 Go version (My money is that its out by Christmas) and if you go selling your 9300 now and get...
Just to reiterate what others are saying. They will overwrite but its highly reccomended you uninstall the old ones first to avoid any driver conflicts.
Once nVidia and/or Dell makes an announcement somewhere about a mobile 7800 card there will be threads about it within minutes plastered all over the net including NBF. Nothing to do but watch and wait at this point.
I would imagine certain areas would have a bit more of a delay as far as UPS delivery goes. Obviously parts of LA will be a mess for ground shipping of any kind. Parts of Southern Mississippi too I suppose.
I'm keeping my desktop updated and upgraded for today's and tomorrow's games just in case they dont make the 7800 compatible with the current XPS2. Hopefully they will.
Yeah, I have to admit I wasnt expecting much from the lappy speakers but I am impressed with them. Not as good as stand alone speaker system but for what I use the laptop for (computing, games, movie watching) they are more than adequate.