It also depends on your level of Ocing. I.E. how much you want to do it. If you want to OC a lot, get some very good RAM (G. Skill LA's) or some Corsair XMS. But if you only want to do a little bit of overclocking, then you can get away with lesser quality RAM (Kingston, crucial, corsair). Dont get Value RAM if you intend to OC. Some people can OC really well with value ram, whereas others get no such luck. It's almost a luck of the draw with Value ram. Only get that if you are the end user who does nothing but goes online and their box is a toy.
Now I guess it is really up to how much money you want to spend.