Ok, so I had a 500GB Hitachi Travelstar 7200RPM drive in my early 08' MBP that I installed in December 2009. It was fast, reliable and pretty quiet. Apple swapped me my old one for a brand new one, so my Hitachi went with that one. Anyways, I have a 750GB 5400 drive in this one and want to get a new one with 7200RPM. Now I will be honest and say that I like the extra storage I have in this one. Hitachi doesn't make a 640GB or 750GB 7200RPM (atleast not sold at Newegg.com), but the one I had (perhaps a newer version) is $60. I see that they have a Samsung 640GB 7200RPM drive for $80. As with most HDDs, it gets mixed reviews, but overall is 4 eggs out of 5. I am sure the Hitachi got the same sort of reviews. Is the Samsung a good drive? I mean for $20 more I am getting a little bit more storage.. I see the Seagate is about $100 for a 750GB 7200RPM, but I have mixed feelings with Seagate. Any advice is appreciated. I am ordering RAM as well, so will be pulling the trigger tonight..