Thanks for the replies. I posted this question because I have about 110Gb of files I seldom access (music, videos,pictures, etc), and I thought that by placing all these files in a 2nd partition that I would be reducing the distance traveled by the drive's head in the system partition, hence increasing performance.
Of course I could move all these files to a 2nd physical drive, but I don't want to have a 2nd drive permanently connected to the system, specially since as I said it would be seldom accessed.
I found this article which supports the idea of performance increase by partitioning the drive:
http://www.acronis.com.au/resource/tech-talk/2004...-introduction.html