I would add the Alpamayo to this list. It is spectacular. I am also salivating at the prospect of Cotopaxi, but I am not sure if volcanoes are your thing.
Alpamayo is beautiful; it would be great to visit the Andes and behold the vast frozen wonderland. Volcanoes tend to have very wide profiles - Cotopaxi, Rainier - that make their contour profiles imposing. Rainier in particular has a complex array of reentrants and spurs. I find the slender, titanic pyramid of mountains formed by uplift - K2 in particular - preferable.
Volcanoes are hot and remarkable; I have a great fondness for caldera geophysics. The idea of Yellowstone exploding in a colossal explosion of lava and ash astounds me.