First up: Mount Fuji, Japan. One of the most famous volcanoes in the world, and looking at this picture it's clear to see why.

Secondly: Mount Stromboli, Italy. Stromboli is famous for its "fire-fountains" and shown in tihs picture is a perfect example.
Thirdly: Kilauea, Hawaii. This low viscosity basaltic magma pouring from the volcano produces these spectacular lava flows...

...and last but not least: Parinacota, Chile. Its difficult to pick the "most beautiful" volcano from the Andes as there are so many equally fine candidates. However, for me Parinacota has just a little something extra.
So, the contestants are lined up and waiting for you to decide which of them is most worthy of the title "most beautiful volcano". Cast your votes!