Some people will think its worth it, some people won't.
I'm in the same camp as a lot of people on here, (including anybird123) just because its a new shiney thing to play with
And at the end of the day, if your a graphics whore like most of us are, (otherwise you wouldn't be spending £600.00 on a graphics card) then a 25% increase is welcome.
Saying all that, I actually haven't made my mind up yet, whether to get one or not. Not because of money, just because I am in no rush to do so, so will just let the pre-order free for all, die down first.