Not sure if you decided on anything yet, but I have a 7200 RPM drive and it has been in my system for over a year with no problem. And just so you know I have the 60GB launch model.
There is a small increase in speed due to it, duh. While I never did the research myself, I saw, recenlty a PS3 Slim thread that compared speeds, that someone replied with tests of the phat PS3 using a 5200 and 7200 RPM hard drive. The 7200 RPM outperformed, but not by much.
Also, the HD that I got had a 16MB cache, compared to 8MB. I am not sure what exactly that can do to performance, I just took the word of a friend of mine who knew more about HD's than I did.
This is what I got.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136280
All I can really say is, the speed isn't going to be a big problem. Just find a company that you trust and find a price/size that fits you. And go with newegg.
