I would say the 2500k is a early candidate to processor of this decade. While we can only really see down the line just how potent it is in relation to tech at that point, I really can't see processing power going further much more, I see Intel and AMD alike focusing more now on a balance between IGP and Processing power. By producing a potent IGP, down the line the need for a dedicated card will become obsolete, when that happens PSU's will be toned down and Motherboards will be minute without the need of PCI-e ports.
If money is not a problem, definitely the core i5 2500,
otherwise the Phenom II x4 965