looking at replacing my 6970 as my brother wants it , i am looking at the gtx580 because i cannot get the fund for the 7970 .
which brand is best /cheapest ?

I would wait a few weeks Nvidia might cut there prices seeing the 7970 are a bit cheaper than expected and are getting good reviews,  the cheapest 7970 I have seen is 420 quid.

easier said than done lol , if i wait to long i will spend the money of something worthless