Thanks all, some interesting posts and links there, will make for quite a good read later today. I'm sensing that water cooling is the favourite but prices like what Damien C Quoted are way too high for me (useful post none the less).
I feel I have left a lot of info about what I have now so I will add that just to clarify.
Currently using an AM3 AMD Athlon II X4 630 CPU on a stock cooler at stock speeds.
Just realised my Mobo is passively cooled so thats no longer an issue.
A Radeon 5750 from xfx, pretty big fan on this one but since system noise increases the most when gaming I'm assuming most of the noise is coming from this or possibly the CPU (Play RTS mainly, Starcraft 2, Supreme Commander etc)
PSU is pretty bog standard Arctic power from ebuyer, The noise from this is just a little bit higher than I would like. but acceptable as its only really when my system is under load that the noise gets too annoying.
Hard drives are perfectly quiet for me though I may look into an SSD further down the line for other reasons
The whole system cost around £400 so £730 is daft for the cooling, especially as I don't overclock.
Would also like to ask if anybody has any shop links for any of the components they use, I use ebuyer myself but don't mind using others