I've searched the web for a couple of hours and found pretty conflicting answers. In short: I have a 2.53 GHz 15" Unibody late-2009 MBP and I need to upgrade my internal HD. What's the best one? It looks like the main choices are Seagate and Western Digital, but even within those, there are different model names (Momentus, Barracuda, etc...). Is one quieter than the others? Also, what's the practical difference between 5400 and 7200 RPM? Does it depend on how heavy your usage is? I do run Parallels pretty frequently, so my computer does tend to get close to maximum CPU use. Thank you!