Which RAM for an asus P5Q Pro Turbo and where to buy DDR2 these days?

Hi, I have an asus p5q pro turbo with 4GB crucial ballistix ram, I want to upgrade to 8GB(have x64), Im looking to get rid of the existing ram and get all new. I was looking to try G.Skill having heard good things and not tried them before, but I cannot find it in the UK for love nor money so I have started looking at OCZ reaper, have also seen kingston hyper-x, which brand/model is considered the best and also where can I buy DDR2 in the UK, most of my usual 1st stops only have DDR3, the only DDR2 I can find is obscenely priced.

Any info/assistance is grately appreciated.

Thanks,