Well just imagine an overclocked q6600 with the forthcoming 8800 gts and Alan Wake, unreal tournament3, Supreme Commander, Crysis etc. You get the picture

Also sell your other bits on in another system prior to christmas to make the transition easier.
Better list here:
==================Quad Core=====================================
Alan Wake - Ground up quad core support.
Bioshock (Unreal Engine 3) - Quad core support.
Call Of Duty 4 - Ground up quad core support.
Company of Heroes - Ground up quad core support
Crysis - MP Beta Dual Core support, full game ground up Quad Core support.
DiRT - Ground up quad core support (up to 8 cores reported).
Flight Simulator X - Quad core support with patch.
HL2: Orangebox and all other source engine games after release - Full quad core support
Lost Planet - Ground up quad core support.
MOH: Airborn (Unreal Engine 3) - Ground up quad core support.
(hl2:ep2 + portal use full quad for rendering, ai and everything else, not just the particle system).
Stalker - Quad core support with 1.0004 patch.
Supreme Commander - Ground up quad core support.
World in Conflict - Ground up quad core support.
Unreal Tournament 3 (Unreal Engine 3) - Ground up quad core support.