Vegas are the only profitable choice out there in Gpu mining. I mean truly profitable as there are many other cards which can give you a low profit by mining with them but Vegas are doing great and I think are the only cards to make 0.16 mBTC as a minimum per card daily.

You can buy them now or just wait a little bit as the prices of all graphic cards are going down on ebay very fast , with prices dropping every day. You can build a 6 cards miner cheaper now than it used to be in the beginning of this year.