Well it depends completely on what you're doing.
I have my 3770K overclocked because I use Handbrake a lot for re encoding stuff and here's where it's nice to have that extra grunt available which I get going from stock 3.6Ghz to 4.3Ghz..
For the average Gamer overclocking CPU's doesn't yield any huge improvements unless they have some crazy multi GPU setup. An Ivy or Sandy i3 is enough for any kind of gaming and as far as I know wouldn't bottleneck even an GTX680/7970.
For the average Joe who doesn't play games and only uses his computer for browsing the internet, paying the bills, watching Youtube and Netflix, listening to music, using Microsoft Office or OpenOffice -> a G530 is more than enough. (before I upgraded my CPU to 3770K I had a G530 in this very same rig and I upgraded because I was getting into using Handbrake and wanted better performance, and I had the money to do the upgrade)
Before I downgraded to G530 -> I had a 2500K and a GTX470 rig. 2500K running 4.8Ghz and a GTX470 overclocked as far as it was possible (literally maxing the core clock without messing with the GPU bios). I gamed a lot. And participated in distributed computing projects. My interest in both died. Decided to get rid of the CPU&GPU before Ivy Bridge came (managed to squeeze 185€ from the CPU while I paid 210€ for it, although it helped that it was a rather "silver chip" not golden good but very very good.) Then purchased G530 and a used HD5750. Was happy until I got tired of the poor performance in encoding..
As for overclocking GPU's, overclocking them has never died. If the OP can get his cards from the stock clocks of 900 core 1026 memory (nvidia reference) to somewhere around 1000-1100 core and 1050-1200 memory he would see a very nice increase in performance.
Sent from my GNote
Well I actually went and ran Juce's x264 benchmark 0.1
3.6Ghz I get avg fps of 16.833 on medium preset and 2.593 on very slow preset. On 4.3Ghz I get 19.963 and 3.083 respectively.
Increase of 19.44% clock speed results in 18.594% and 18.897% in encoding performance. Worth it? Hell yeah..
And the test folder was on my SSD (Intel 520 60GB) and not on my 3TB drive so that might affect the results a bit.
Running it on my 3TB I get these results with 4.3Ghz medium 20.133 very slow 3.109
Not gonna bother running the test again at 3.6Ghz on the 3TB drive (which is WD30EFRX fyi)
Edi2: And now that my router came back online...I can show you the actual results if you want to see them.
Updated the original text a bit. Sorry if it is messy! I tend to type a lot when I get going..