A suggestion is "slower is better" because it generates less heat. So, skip the 7200 RPM drives and stick wtih 5400 RPM or 4200 RPM.

Also, Hitachi/IBM and (I think) Segate are recommended drives for the player because they came with it initially. You may want to have both hard drives be from the same manufacturer though.

Height is also an issue. You can read all about that, and more issues, in the Disk Upgrade Guide. Make sure you are comfortable with the process in that guide before doing the upgrade.

I purchased a Hitachi/IBM Travelstar 80gig 4200RPM drive (9.5mm) and it's worked great. Skip the retail stores and save time by buying online. Here's a list of notebook HDDs in a recommended brand that should work, from an online retailer that I've trusted for years. Lucky you, the price for a 4200 RPM 80 gig is *half* what I paid a year and a half ago.

Good luck.