"...I am a big fan of monuments and building." How about historical and war monuments?
If so, I recommend the Soviet War Memorial and the Schwarzenbergplatz, for the Austrian commander against Napoleon, although still beaten decisively at Dresden by the French. Both these monuments are large, located not far from each other. Also, not far from Westbahnhof on an island in the middle of the street is another military monument, a soldiers' memorial, to the events of 1809, ie, against Napoleon. But the biggest military monument is at the Deutschmeisterplatz, where again the events of 1809 are part of the memorial. The Austrians focus on 1809 even though in the end they still were defeated in 1809.
For individual monuments see the two in front of the Hofburg, the Archduke Karl (of 1809 fame) and Prince Eugen, who was the Habsburgs' most victorious commander since he never lost. While you're in that area of the Hofburg, a few mins walk , I suggest also the Maria Theresien Platz, the monument to the Empress Maria Theresa surrounded by her commanders. The Albertina should not be missed either if you're interested in buildings and monuments, aside from the art exhibit inside.