Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I put 4GB in mine and it's never used more than 2GB. Just to warn you.

I'm handbraking a DVD at the moment and it still says 2.5GB free.
 
Well the OP says that his needs exceed what he currently has, so lets assume he knows what he needs is correct. The price looks pretty decent, and its OWC so generally quite trustworthy.
 
Just a warning with that: you said you have the unibody MBP, but that RAM is DDR2, not DDR3 which is what you'd need for the upgrade (though I'm not 100% sure if DDR2 works with the unibodies in the first place)

Also, if you use virtual machines or run a few programs at one, or use photoshop, having the extra RAM helps.
 
Ah yes, I forgot to check that it was the right RAM for your unibody, I thought that was a bit cheap for DDR3 stuff. For your Macbook pro, you specifically need 1066MHz DDR3 SDRAM.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.