Thanks Zen. I did some research on these coolers and they seem to provoke violent disagreements on various forums.
They were last weeks special offer on my retail site.
1 X Intel Core i7 920 D0 Stepping (SLBEJ) 2.66Ghz overclocked up to 4.00GHz! (Choose overclocking option above.)
1 X Gigabyte EX58-UD5 Intel X58 (Socket 1366) PCI-Express DDR3 Motherboard
1 X Patriot Viper 6GB (3x2GB) DDR3 PC3-12800 (1600MHz) Low Latency Tri-Channel
1 X Noctua NH-U12P SE1366 CPU Cooler (Socket LGA1366)
1 X Arctic Silver 5 Thermal Compound (3.5g) (£545 for the lot)
It's a nightmare deciding which one to get. I 'll decide finally tomorrow. I'm off work so I can do some further research and then ring them.
If they'll vary the offer I may yet go for the Tuniq, the H50, or the Megahalems.