It seems entirely logical to me that they should, but so far most of them I see just mention, "Microsoft Windows 7 Professional x64, Microsoft Windows Vista Business x64 (SP2 or higher), or Microsoft Windows XP Professional x64 (SP2 or higher)".
Does "or higher" also reference the Ultimate versions of these OS's, or just the Service Packs? It'd be nice if I could find a few people who are running stuff like Maya or 3DS Max of Windows 7 Ultimate right now.
I'm trying to be extra sure before I get anything.
Yes they do.
If not Ultimate is very kind to allow you to run in compatibility mode.
Ultimate is really no different than Professional or business, just adds on the capabilities that Vista had in their professional bundle and charges you more for it.