Just a FYI, I have had it running on 2003 since 8/04, I have encountered few issues, all of which were resolved fairly quickly, some with the help of TAC (also have it running with failover). I think it all depends on your enterprise and the direction you are going, except of course for any other IPCC products...CCM, IVR, ICM, all of which have to be on 2000...for the time being....