My 1st Build Complete, Overclocked. Suggestions?

After months of research and saving up money, I finished my first build ever yesterday.

My budget was ~$1,500 (w/ a new monitor which costed me $140)
Here are my specs:


Case: Corsair Obsidian 650D
Mobo: Asus Intel Z68 ATX DDR3 2200 LGA 1155 P8Z68-V PRO/GEN3
CPU: Intel i5-2500K
Heatsink: Corsair Hydro Series H80 Liquid Cooler
GPU: MSI N560GTX-Ti Twn Frozr II 2GD5/OC
Memory: Kingston HyperX 16GB (4 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800)
PSU: Corsair HX Professional Series 750-Watt 80 Plus Certified
SSD: Crucial 64 GB m4 2.5-Inch Solid State Drive SATA 6Gb/s CT064M4SSD2
HDD: WDigitial Caviar Black 1 TB SATA III 7200 RPM 64 MB

At first I was extra careful with everything since I am a novice, I didn't want to break or mess anything up.
Especially when I was pushing down the latch on the motherboard to put the CPU in place, I was very nervous!

But everything ran quite smoothly.

Although I am far from being a heavy user, I decided to build a high-performance PC to have that heavy using option available in the future. So I decided to overclock and here is what I've achieved so far.

i5-2500K from 3.3 GHz to 4.7 GHz (Temperatures around 60-70 degrees, core voltage of 1.368V under load w/ prime95
Memory from 1333 to 1600
MSI GTX650 Ti - Tweaked a few settings to get 78-79 degrees under full load w/ FurMark

I am quite happy with these settings since like I mentioned before I am not really a hardcore user.

With that said, is it a good idea (for stability, reliability, and durability) to just use the stock settings unless I download intensive games like BF3 or Skyrim?
Or is it okay for me to keep using my pc under these settings?

And also I would love to hear a few tips on better air cooling/fans.
All my fans are stock and my intake is from the front and the top (both 200mm)
And my exhaust is out the back through H80 radiator.