Given most processors are dual or quad core at the moment, what are the downsides of getting the 6 core I7-3930k in terms of software limitations, if any? And hardware?

I'm looking at upgrading my current dual-core, and at the moment price isn't an issue but I want to ensure I'm buying something that will be compatible with parts for up to 2-3 years. To give you an idea, I bought a pentium 4 a few moons ago with RD ram, just before SSD RAM won that battle; for obvious reasons upgrades became extremely expensive once it was effectively discontinued as mass market technology. Thus a 512meg RD RAM stick which should have cost me £40 went for about £150. I'd like to avoid that situation!