ThinkCentres Upgradability

I am thinking of getting a new thinkcentre…cause i really like the small compact factor of the thinkcentres…

i have my eye on the thinkcentre m series since they have the PCIE…

but before i go buying i want to know can i put another network card in it?

also which is the cheapest nvidia 6800 series card?

i am thinking ill need atleast 1 gig ram in it too…

i will be using the pc for mostly games and gfx and normal pc usage and it will on 24/7…

should i go for the thinkcentre or am i better off creating a new pc with a amd and a case mod ??