Overclocking adds heat and noise, but doesn't necessarily give you any real-world benefit.
Even with a GTX680 graphics card you might find it difficult to find a gamer that overclocking the CPU would benefit you.
If it's for converting videos and you use your CPU then yes, that will likely benefit. I don't convert often but I do on occasion so I only overclock when doing those tasks and then I set everything back.
*I overclocked my CPU which was actually BELOW 30C in idle because my CPU fan was off. When I overclocked I lost the power savings benefits and my fan actually had to turn on despite my CPU reporting under 1% usage most of the time.
It's fine to overclock, I just recommend you don't without an actual reason and enjoy a quieter, cooler experience the way the CPU was designed to provide you.
I'd even give it a try at stock speeds and compare the fps. This way you'll know if it helps any. If you're easily getting 60 fps in BF3 there truly isn't any reason to overclock the CPU, unless of course you're encoding video or something of that sort.