What setup to keep?

I actually got an intel Mb with 2 X 256 of mushkin PC-3200 lvl-II BH-5 and thinking of adding mem. I would like to know if it's better to buy 2 more 256 of other brands or selling my mushkin and get 2X512. This is for a gaming comp.

2x512 would be better.

Any specific brands name I should get? Since neweggs doesn't seems to have mushkin PC-3200 lvl-2... Or can buy any good online shops that accept paypal.