noob question re partions

[ThriceNightly]

I have never run partions on a hard drive, so appologies for this very simple question

I am rebuilding my pc with a 160gb hard drive and will be instlalling win xp (mce 2005)

when i install the operating system is it worth creating a seperate partition for it and how much gig should I allocate.

 

[ThriceNightly]

usually when creating partitions I create it 1/3

for example

200 GB drive = 1/3 =

50GB primary (OS) / 150GB slave (downloads/important files)

Thats usually how I work my drives.

thanks for the reply