I'm still "casually mining" on 3x shader-unlocked liquid-cooled 6950's in my machine - it's a gaming rig, not a mining box.

The price of electricity is very barely worth it during peak hours, running it overnight is still rather profitable.

It sounds like you're wanting to buy a forth. Well, they're still great cards for gaming, and with four of them in crossfire you're still going to be able to blow the pants off pretty much every game. You won't make back the outlay for the card before the reward halves, unless you get it for next-to-nothing.

If you're still keen on getting the card, even not for mining, wait a few months and pick up a cheap ex-mining card!

Otherwise, keep mining until it becomes unprofitable. Surely that makes sense.