OC build vs Non-OC build

[Nightbeat]

Hi. finished choosing all the parts for my rig, but everyone that hears I picked the 3470 over 3570k tells me I did a mistake, and that a non-overclocked i5 won't be able to do much.
I did not order the parts yet, so there is time to change things.
I will be gaming mostly, recording gameplays alot to my HDD using dxtory/fraps and rendering the files with vegas (sometimes!). other than that? not much.. surfing the web maybe.
Will CPU OC benefit me? do I really need it? If I choose to OC I'll have to spend like extra 200$ for a good mobo and a CPU cooler..
Current parts I picked are these (no-overclocking intended):

Intel Quad-Core i5 3470 3.2Ghz 6MB Tray
ZALMAN 7000V Al SI EDITION
Gigabyte GA-B75M-D3H or ASRock B75M
Hynix 8GB 4GBx2 DDR3 1600 CL11
Intel SSD 120G Sandforce 2281-330 Sata 3
Seagate 2TB Barracuda 7200RPM 64MB 1TB PLATTER
SAPPHIRE 7970 3GB GDDR5 HDMI RETAIL
Seasonic ECO 600W

If I want to have an overclocked machine that fits my budget I'll have to choose this:

Intel i5 3570K : IVY BRIDGE, CORE I5, S1155, 3.4Ghz - TRAY
Scythe MUGEN III REVB
ASRock Z77 PRO3
TRANSCEND 8GB (4GBX2) DDR3 1333 CL9
GIGABYTE HD7970 "WINDFORCE 3X" 3072MB GDDR5
ENERMAX NAXN 550W
SEAGATE 7200.14 1TB SATA3

Had to give up SSD, lose 1TB of HDD space... and it crossed my budget limit by a little bit... is it worth it?
Which one of them will be better for serving my needs? maximum gaming performance and being able to record/render gameplays sometimes with no lag?
Thanks a bunch!

 

[tiraides]

The stock speed of the i5-3470 is only 200MHz slower than the i5-3570K, even with Turbo Boost engaged to its maximum levels. You're fine there.

You don't need a third-party CPU cooler unless you live in a very hot environment. Even then, I'd recommend a better CPU cooler like the Cooler Master Hyper 212 Plus/Evo -- but again, only if you need it.

Can you find a cheaper DDR3 1333 CL9 kit than the Hynix kit you're considering? You don't need DDR3 RAM for the i5-3470.

Where are you buying your parts from? I've never heard of the Seasonic ECO series before.

 

[Nightbeat]

You don't need DDR3 RAM for the i5-3470.

What do you mean by that?
I live in europe, this is where i'm getting the Seasonic ECO. it's 85% power efficiency 80plus bronze.
The Hynix RAM sticks are actually the cheapest ones avaiable. cheaper than any corsair/kingston/g.skill stick

 

[tiraides]

That's a typo on my part. What I meant is that you don't need DDR3 1600 RAM. But given the comparative price, disregard what I said earlier.

80 Plus isn't everything, but Seasonic is a good PSU manufacturer. The ECO series is new to me, which is why I asked about it.