GTX 780 is at a nice price in the UK right now. All depends how much you want to spend.
£300 at most I think, I can probably get £80-100 on ebay for my 560Ti so I can justify a few hundred quid on a card.
Thanks, I'll start looking at 780's then. Are there any new cards on the horizon coming in the next few months that I should be mindful of?