Problem - OS X uses HFS+ and Vista uses NTFS for file systems. They can commonly use FAT32 as their intermediary but they both lose the benefits of their native file systems. One, FAT32 only supports 4gb file sizes which can be a problem when working with video. Two, NTFS can only be read by OS X and not written, HFS+ cannot even be natively read by Vista at all. Three, the OS X resource/data forks can be corrupted when stored on non HFS+ volumes.
You can
move your home directory to an alternate volume in OS X, but I wouldn't recommend putting it on a FAT32 partition.