Interesting how many of the choices were streamlined steam locomotives. In the steam era, suspect few votes would have gone to them - overturned bathtubs, etc. Tastes change over time. Additionally there were only a handful of them - so scarcity probably contributed.
No citing of the very handsome conventional 4-8-4's; my choices: NP A2/A3/A4/A5, D&RGW M68, MoPac 2200, CNR U2e, CPR K1a, Soo Line O20. Some outliers, but among my favorites: CB&Q O5 and WM Potomac.
Oh, wait. Forgot the Pennsy T1 !