Well if support is a problem I can recommend Vista 64 since support for it is great right now. Lot of new machines are sold with V 64 now, so support for it should be no issue at all going forward.
Other reasons to get vista? DX 10, better security, great eye candy, but I usually advise Vista for new PCs since XP still works great too, no compelling reason to switch.
If what you are asking is Ultimate worth it over Home premium or business - well, Ultimate offers very little really, I have it but if I were to do it over I'd just buy home premium.