This is the 16 million dollar question.... Well, maybe not that serious, but something I've been looking into a fair bit lately. Here are my thoughts, please take into account I don't know very much at all, just learn as I go, but I'm sure my thoughts count for something.
I would get a Seagate hard drive possibly a Momentus and in your case, as you have a 15" MBP I would get a 7200RPM. I'll give reasons for my opinions, which are only opinions; 1. My Macbook came with a Seagate, so Apple sell you the machine with them in, and a friend of mine who works as an Apple service specialist told me to go with Seagate. 2. I have a 13" MBP, from what I've read, 13" MBPs run too hot with 7200 drives in, I looked on the Apple site and went the page where you can configure your purchase, and sure enough you can't request a 7200RPM speed drive in a MBP 13". However, if you go to the 15" and above you can select a better/bigger drive with 7200RPM speeds.
I'm believe the faster drive would be ok in my MBP, but I don't know if this could affect my warranty or something.
So faster and bigger in your case, why not?
It has occurred to me that you don't have a Unibody Macbook Pro, so I would get the specs in respect to the 7200 point for your model, but I can't see an issue, but please check.
Hope that helps to some degree.
Good luck, post back with your decisions, thoughts and choices (related to this issue ;-))