Why, the Polish TK-3. Isn't it everyone's?
I'm more generally interested in armor, and don't have a clear favorite. I especially like the Grant and Panzer IIIj for the Tobruk battles, the Wehrmacht Tiger II's and the ISU-152's in Hungary, and the Shermans of the 4th Amored Division in France. IS-II's in Berlin are cool too. And then there's always ...
I like em all! Just interested in the history and dynamics of it, and very glad I learned what I know in an armchair instead of staring down the muzzle of an enemy tank.