After reccomendations on cooling setup

Looking at updating the cooling system of a PC i've got, the current fans are a bit tired/noisy- the fan in the heatsink is particularly bad. Here's my build:

Case: Cooler Master Storm Scout
Heatsink: Cooler Master V8
MB: DFI lanparty x58 t3eh6
CPU: intel core i7 920
RAM: 3x2gb corsair ddr3 1600mhz ram
GPU: radeon hd4870

So, where do I start with setting up a new cooling system? Has anyone had any experience replacing the fan of a Cooler Master V8 heatsink, and, if so, what with? I'm not sure what options I have in terms of fan control either.

Cheers!