depends what you mean by "good".  if bitcoins fall to a $10 or even less, you could be mining a while to see any kind of profit..... if you are predicting that the price goes back up to $30 or more then you should be able to make a profit. For only 1 card 340Mhash is good.  But as difficulty increases you will soon notice that 340 just doesnt cut it like it used to.  with prices where they are now, youre better off buying bitcoins and saving electricity.