Are you going to be doing very memory draining things than the average person? Such as video editing and graphical design? Becuase 4 gigs these days is still overkill for almost everyone.
2GB is still plenty for most people's needs and gamers.
The memory I like to recommend the most right now though are these.
I have 2 sticks of the exact same stuff in my putter and it is AMAZING for the price, just shockingly good for that cheap.
Actually all G.Skill memory is.
And if you feel like going on the pricey side of things with memory then this stuff is ridiculous as well.
Pricey though and you really won't "need" it but the HZ's are still kickass.