Future-Proof Budget Rig

After a multi-year absence from the PC gaming circuit I'm looking to enter the fray once more. My objective is to build a budget PC that has a stable enough base to allow for gradual upgrades over the next few years. The CPU / Motherboard combo suggested to me is the AMD A-10 5800K and ASUS F2A85.

So, a few questions:
1) Will Socket FM2 AMD chips be around for a few years?
2) Is AMD FM2 a decent base to start a gaming* rig? That is, do I need to be looking at a different chipset entirely?
*when I say "gaming", I an not concerned with running the latest and greatest games at full detail at the highest resolution possible. I've got a huge catalog of older games (Doom 3, RCT3, Homeworld 2, Company of Heroes, etc.) to work through, with some newer games I'm interested in (Starcraft II, Crysis 2, etc.)
3) Down the road, I do plan to buy a dedicated GPU. Once I do that, will my CPU become the limiting factor for this build?

If it helps: My plan is to use that CPU / MOBO combo and use the other parts listed here to build my PC: http://pcpartpicker.com/p/AOWd
I already own a suitable case, hard drive, and optical drives.

Thanks.