Vienna: Composer Museums and Sites

[Archaic Torso of Apollo]

Am planning a trip to Vienna in January or February. Although I've been there a couple of times before, I haven't done serious "composer sightseeing." I plan to fill that gap on my next visit.

Are there any composer museums or composer-related sites that people want to recommend? Of course I can get all kinds of info online, but it helps to get a personal perspective. This for instance

http://inmozartsfootsteps.com/highlights-2/composers-sites/

states there are 3 museums just for Beethoven - can anyone compare and contrast them? Any other recommendations for music-related sites are welcome.

[Florestan]

Try Haydn's house and museum located on a little street near the Westbahnhoff Railway Station end of Mariahilferstrasse, left side looking the station. Last time I was in Vienna it was on its closed day. 

[Opus106]

Zentralfriedhof?

[Cato]

Not to be forgotten is a fairly new Arnold-Schoenberg-Zentrum

See:

http://www.schoenberg.at/index.php?lang=en

[Karl Henning]

Mmm, nice. I'd go to Vienna just for that!

[Archaic Torso of Apollo]

Thanks, the Schoenberg Center does look very interesting.

When you press the button, a very polite young man will emerge to explain to you that you have probably come to the wrong place, this being the Arnold Schoenberg Centre (where people only arrive by mistake, appears to be the inference

I'm looking forward to having this experience