I didn't want to have to backup a 250Gb hard drive all at once.
You wouldn't have to even if you had only one partition. It depends on
what backup software you use, but generally you have the choice of
what folders you want to back up.
If all you backup is data, it can sometimes be facilitated by having a
separate drive for just data.
I have just
games on one drive, heavy graphic programs on another,
I don't at all understand separating two kinds on programs, each on
its own partition. In general programs are programs, regardless of
what type they are, and they are almost always best kept together.
Do you back up the programs? In general, backing up programs is
useless unless you do it as part of an image or clone of the entire
drive. That's because the programs have entries in the Windows
registry and other supporting files within Windows. So backups of the
programs are useless without a copy of the Windows they were installed
under. For that reason, it hardly ever makes sense to separate
programs and Windows on different partitions. All programs should be
installed on the same partition Windows is on.
That's a *bad* thing to do, and *hurts* your performance. The
main performance issue with the page file is the time it takes to move
the drive's read/write heads to and from it. The way to minimize that
head movement time is to put the page file on the most used-partition
of the least-used physical drive. For almost everyone with a single
drive, that's the drive Windows is installed on, C:.
For most people who are not dual-booting, either one or two partitions
(depending on your backup strategy) is best.
You might be interested in reading this article I recently wrote about
planning your partition structure:
http://www.computorcompanion.com/LPMArticle.asp?ID=326