We would not recommend you upgrade to Vista. There are lots of problems with it, and some we're sure haven't been identified yet.
If you aren't readyt to upgrade to XP or 2000, it would be best to stay with your older versions of the Suite 4 programs. When you are ready to upgrade your OS, then get the Suite4 program upgrades. Microstudio 4.0 has incredible error correction so your imported files will have very clean lyrics.