GTX 680 Benchmark scores.

[Solace]

A 670 is practically as good as a 680 and like 100 bucks cheaper.

Or you could just get a Titan, lol.

Absolutely right..
If you intend to play at 1920x1080 or lower, a 670 is the way to go.
The performance is virtually identical.

lol Titan is a monster.. eesh...

As for worrying about frying your PC with an overclock.
Overclocking is easy. Just as long as you take it slow and you monitor temps.
It's almost common sense.
You can just look up a guide and use that as a reference, as to what you need to do, for your cpu/mobo combo.
Take it step by step..
Installing the aftermarket cooling can be fun and it looks cool too. :P

But don't let me talk you into breaking your computer..lol..