I don't repartition very often but I've never had any real problems to resize and add/delete partitions in XP

and XP shouldn't have a problem with multiple partitions; I have 1 partition for Windows, another for installed applications, another for my page file, and many others for different kinds of data, only problem with so many partitions is moving files between them isn't as fast as moving them around in the same partition :/ but hey, it keeps fragmentation segregated, so there :p