For the most part a 'corrupt partition' is actually referring to a corrupted filesystem. Filesystems are contained within partitions(1). So if the filesystem in one partition gets corrupted, the filesystems in different partitions on the same disk will not be. That said, the same event (abrupt power-down, others) that corrupted one filesystem can also corrupt other filesystems on the same disk.
Actually corrupting a filesystem takes some doing these days. I've seen some pretty bad NTFS pukes, but they were all related to exceptional events. A good way to cause problems is to yank the powercables out the back of a Windows server while it's doing heavy I/O. For SAN-attached storage (not your problem) sometimes if the SAN hiccups for some reason the OS can react strangely; I had a case on Server 2003 where just such a hiccup caused Windows to flag about 20GB of the partition as bad-clusters (they weren't, a
chkdsk /F /R removed the bad-flag from those clusters). Abrupt power loss is probably the most common cause of such problems. Having your drive partitioned so that your heavy I/O applications are on a different partition than your OS boot environment means that when the power is yanked the chances of boot being affected are much smaller.
(1) Unless they're part of a volume management system like LVM, or Microsoft Dynamic Disks, at which point things get a bit fuzzier.