I strongly recommend to NOT mine SHA 256 coins (Bitcoin, Namecoin, Devcoin) using a GPU. You are better off connecting your GPU to a multipool that is mining scrypt coins and converts them to BTC automatically.
Also I currently wouldn't advise to invest in asics unless you have lot's of spare money to buy big ones and get electric power cheap.
Very much agree. You can hardly get profits in buying mining equipment now.
You could use profit-switching pools such as
https://www.multipool.us/ and
http://clevermining.com/ to mine the most profitable coin automatically.