7950 (I get 1200 kh/s with 2 cards) and R9 280X (I've seen people getting 800 kh/s with a single toxic edition card) are probably the best for mining.
Thanks bro for answer kh/s or Mh/s which is greater sorry for this question because i'm totally noob here And with this 7950 2 cards how much your per day average of mining?
I used this calculater http://www.alloscomp.com/bitcoin/calculator but it's confusing for me because there are not any kh/s present i can only see Mh/s, Gh/s and TH/s.
Mh/s is greater, for example my 1200 Kh/s = 1.2 Mh/s. You can use this calculator to check the earnings.
http://www.coinwarz.com/
Also, http://www.alloscomp.com/bitcoin/calculator is a Bitcoin calculator. It's no longer profitable to mine BTC without an ASIC miner, that's why most of us mine Scrypt based coins.