In reality, there is no configuration that will fit all those criteria. Good overclocking boards aren't cheap, there are really no "long term" sockets, aside from the current LGA 1150 which will likely lose it's usefulness for future upgrades come August when Skylake is released and really has only one CPU with any capability at all for under a hundred bucks anyhow. And that CPU requires SIGNIFICANT overclocking and cooling to even be worthwhile. Decent power supplies don't come cheap either. When it comes to power supplies, except maybe in the case of the Antec VP-450 for low requirement systems, there's either cheap, or good, not both.
That being said, this is about the best I can do but you haven't indicated whether you also need...