I am not much of an art museum kind of guy. I really enjoy natural history museums and military history museums. Vienna has two good ones.
A lot of the military history of Europe took place in Austria. The Museum of Military History covers all of it. WW I started with the assassination of the Arch Duke Ferdinand of Austria. The museum has the car he was riding in and his blood stained uniform and a great exhibit on WW I.
The Museum of Natural History is very good with an excellent dinosaur exhibit. For us one of the high points was the very good restaurant on an upper floor. A very nice place with table service. Not the typical snack bar of American museums! A great place to get off your feet and have a beer, wine, or coke lite!