First of all, this wonderful museum is a bit hard to find even with a good map. Take any public transport to Südbahnhof (South Train Station). From there, exit onto the street and look right to find Arsenal Strasse. Go right along Arsenal Strasse and follow it for about 5-10 minutes, depending on how fast you walk, then turn left at Ghegastrasse. Keep walking...you'll see the museum, but can't figure out how to get to it. Some of the buildings, called Objekts, look like private apartments. They are. When you get to about Objekt 8, go through there and walk behind them and you'll be able to find your way easily to the museum.
Very interesting museum with lots of military history. The assasination of Archduke Franz Ferdinand provoked an international crisis that started off World War I. The car in which he was assasinated is here, as well as the couch he died on and his blood-stained uniform with a bullet hole.
Lots of paintings and memorabilia regarding the Turkish Siege of Vienna in the 1600s. The hero of the siege was Prinz Eugen (Prince Eugene of Savoy), who later built Belvedere Palace for himself.
Another part of the museum has displays and information on the Austro-Hungarian Navy--yes, landlocked Austria had a navy.
The museum is very large and has several other buildings to visit. We were there for five hours and finally gave up because our feet were tired. We saw perhaps a bit more than half of all there was to see. I recommend you get a nifty hand-held tape recorder, which looks more like a telephone receiver. When you get to something you want to hear more about, you punch in the number that is listed on the display and it tells you all about it. You can end the tape if it's uninteresting and move on. I believe the cost of this was 3 Euros or something like that. It helped in our enjoyment of the museum.
There is a little cafe in the main building. Don't get the coffee, it tastes instant. Instead, if it's a nice day, get a beer and sit outside in the Tank Garden and enjoy the sunshine.
When you get back to Südbahnhof, there is a little grocery store at the far end in the front for you to get liquor, mixers, chips, snacks, milk or whatever you might want.