I have 2 partitions on my pc, 1 for xp, and the other for all software/games etc. But the thing is, when i wana reformat and reinstall windows, i ususally end up reformating all, cuz my other drive has a load of useless stuff that got there somehow, but as they said, having partitions is cleaner, and makes it so u have les fragmentaion, thus increasing performance. But if you are using an image tool, it can be very usefull.