Hi. I am running Mountain Lion on my MacBook Pro early 2008, 2.5 GHz Intel Core 2 Duo, 4 GB 667 MHz DDR2 SDRAM, NVIDIA GeForce 8600M GT 512 MB and I am very satisfied. Still fast like new however I wonder if there is any better OS X for this machine even though I`m only using the basics: watching videos, browsing the internet. Thanks!