Upgrading system - i5 vs i7

Hi,

I'm looking to upgrade a few components of my system. I just got a new SSD, and not long ago got a new gfx card (the other took a turn for the worst after a bowl of water was dropped onto my pc... not cool).

Anyway, I was looking at some pre-OC bundles from scan.co.uk. The components included are:

- Gigabyte, MSI or ASUS Z77 board (Z77X with the gigabyte and i7 cpu).
- 8GB Corsair Ram
- Corsair H80 Hydros cooler (or Be Quiet! Dark Rock advanced, but the WC seems nice anywho for a few pennies more)
- Overclocked CPU to 4.3 or 4.5 GHz. (Think I'm going to go 4.3 here, the extra temp and potential noise provided by that little extra OC isn't really priority with me, and I want a fairly solid system, not something that's on the edge of spontaneous combustion).



So the main question:

i7 3770k OR i5 3570k. (or even i7 2700k if anyone would recommend!)


It's been 3 years since I was last shopping around for computer parts, and it'll probably be another 3 before I do again. I want something that'll last me 'til then.

My usage:

Some gaming (WoW, CoD4 - nothing major, but I tend to multitask a lot while gaming)
Usage for a lot of the day just with standard web browsing and music playing etc.
Visual Studio for Programming (again, I'd like to be able to keep multi-tasking while doing this with minimal impact)
Some scientific programs for modelling and stuff (I study acoustics at uni).



The price difference in the 2 CPU's is about 70 quid or so, so quite notable. Is it going to give me the performance or longevity increase to justify that price difference?

Cheers,

Chris