I'm in the process of upgrading my graphics at the moment. I've just acquired a Corsair TX 850W psu and was looking at the GTX 260 (216 core) as with the recent introduction of some newer cards (GTX 275), the GTX 260 has fallen to an attractive price.
My gaming requirements are not extreme and my monitors resolution is only 1680x1050 so the GTX 260 is should be ample. I do however intend to fit one of these as I like cool and quiet:

http://www.scan.co.uk/Products/Artic-Cooling-Accelero-Xtreme-GTX280-for-nVIDIA-GTX200-series-(260280285)

My total budget with the cooler is £200.
I have nothing against ATI and I did think of the 4870 (another bargain in my opinion) but would rather stick with Nvidia at the moment as I'm having no problems with the current drivers.
I have one main concern with my selection of card which refers to 'singing' or 'squeal' from certain GTX 200 series cards. Without sounding too much of a noob, could someone please give me some straightforward information on this please. Any other comments on my choices would be gratefully accepted.

There's sometimes a tiny bit of squeal coming from your base unit while it transitions from 2d to 3d or when it starts working hard. It isn't a loud noise by any means and is soon drowned out by whatever game you happen to be running. I recall hearing similar noises on my 7900GT and 8800GTS. I run at 1680x1050 as well and the 260 (original) copes admirably. The 216 core one should be even better.

Wow thats some cooler, i paid £134 each for my EVGA 260 gtx's, (192 core)

i find there temps good 50-60'c, maybe 70 under heavy gaming,

they can be noisy with fans turned up, but i overclocked mine a little.

id say for a dual slot cooler there not too bad at 40%.

ive had the fans upto 100% and am yet to hear any 'Squeal' coming from them.

I must admit that I was tempted by this as its within my budget:

http://www.scan.co.uk/Products/896MB-PALIT-GTX-275-PCI-E-20-(x16)-2268MHz-GDDR3-GPU-633MHz-240-Cores-2x-DL-DVI-I-HDTV

But from what I've read, the cooler is quieter than the stock one but not that much better in cooling.