I have an spring 2010 15" MBP. I swapped out the original 320gig 5400rpm drive for a 500gig 7200 rpm drive. Partially for the added disk space, and also to help remove the bottleneck of a slower rpm drive. Obviously, having the faster drive is a definite benefit - almost all app's load and run faster (Photoshop plug-ins really run better with the faster drive). The one downside (and perhaps I'm just focusing on this too much) is the decrease in battery life. With the slower drive, I'd average 4 1/2 -5 hours of real usage (running Photoshop, Aperture, iTunes, etc.). The 7200rpm drive seems to reduce that to about 4 hours or so (sometimes more, sometimes less, if I haven't "exercised" the battery on a regular basis). I'm actually thinking about switching back to the slower drive to regain the added battery life. The one thing that needs to be said is...thus far, I really haven't had a need to use the MBP for the full 4-5 hours. It's just that little annoyance knowing that the slower drive will give me a 1/2 hour to 45 minutes additional time. Am I being too much of a 'noid on this?