I have a budget of ~£150 and looking to upgrade my graphics from a GTX 280 as it struggles a bit with games when all the eye candy is turned on. What's the best option going forward considering this will need to tide me over for 12 months or so until my next big PC upgrade? In the main, I'm wanting a card that will give a boost to performance with my favourite flavour of gaming goodness, ArmA 2 (and with ArmA 3 when it arrives). I traditionally lean towards the green team so I've been looking at a GTX 560Ti which is there or therabouts for the budget but would appreciate any other suggestions.
The alternate is go for the crazy-end and go for GTX 480 range hardware, It's hot, but they're still very fast. A 480 goes for around £110 and overclocked (If you have the cooling) they can trade blows with stock 580's.
I upgraded from GTX280 to GTX280 SLI, then gave up on that after a fortnight (hot & noisy even under water) and spent £180 on a second hand GTX580. Best value upgrade I've done for a while, I'd have been equally as happy with a 570 for slightly less money, but I didn't feel a 560 represented enough of a leap. I'd recommend saving a few more pounds and going for a 570. You should be able to get £35-50 for your GTX280 as well to offset the cost of the purchase a little. On eBay of course, very few people on here will want to pay that for a 280!!
£150 is always a difficult price new, as cards tend to hit the £130ish and £170ish mark. But as above, the 570s new are now going for almost the same price as a 560 ti. On the AMD side, if you can stretch to about £180, an HD7850 would be brilliant.
I'd buy a second-hand 570 for that money. A new card isn't going to touch that performance/price balance, and they're very good cards to boot.
I'll be keeping my current card for my bro's machine, but I might consider spending a bit more to go for a 570 then.