I noticed a lot of you have been posting about what hard drive to get for their macbook and I was in the same bout a few weeks ago. I chose to go with the Seagate Momentus 7200.4 500GB for a few reasons. In tests it beat the Hitachi 7200 in almost every aspect except in two multi tasking tests, but everywhere else the Momentus blew it away, even in power consumption, except for at idle I believe. I looked into the WD Scorpio Black, Hitachi 7200, and my drive as much as I could to make the best decision. Before deciding to go with a 7200 rpm drive I had my doubts about power consumption, noise, and heat. After using my 7200.4 for almost two weeks now I've grown to love it. It runs cooler at idle than the stock 5400 rpm Toshiba, and only slightly hotter during HD extensive tasks. Again, at idle and minors HD tasks this drive is virtually silent, and is a bit louder than my stock hard drive when being worked. As far power consumption goes, I haven't noticed any difference in everyday use. If I'm transferring a lot of data all day and things, it might take 15 minutes off the battery tops. But in exchange you finish a lot quicker so it makes up for it in a way. I also read people reporting clicking, lag, and beach balling with this hard drive. I have all of the latest firmware and have not yet had a single instance of any of these problems. I'm pretty sure these problems are more related to the older version of the drives and the older macs. The speed of my macbook is now great. It's very snappy, quick to open apps, download, photoshop, etc...but I also have 4GB of crucial RAM which also adds to this factor. I have not yet had any issues with this drive at all. It installed flawlessly and has caused me no trouble. The only thing that worried me was one time in a car we went over some rough bumps and I did feel the drive clunk, but I've been told all drives do that when you shake them up. It's never clunked or anything on me even when picking the macbook up fast, or even shaking it a bit. So in conclusion, the drive is great in my opinion and I'm very happy with my choice. The sacrifice in power, heat, and noise is very, very minimal, if at all. And the gain in speed and capacity was well worth it. Hope that helped anyone who had the same concerns as me. And sorry for the badly written review haha, I'm way too tired and lazy right now.