Very few people actually find languages to be beautiful or ugly. Usually, when people give an opinion about a language, they are expressing a stereotype about the people who use it. This is why countries associated with the arts and high culture, such as France and Italy, are said to have the most beautiful languages whilst countries which are associated with bad things, such as Germany, are said to have unpleasant languages.
Interestingly, Mark Twain, who was writing before the two world wars and the holocaust, said that it was impossible to convey anger or aggression in the German language. The language has changed little since then, but our perceptions of its speakers (which are very outdated) have changed immensely. Our perception of accents is the same. Often, accents that are considered to be unpleasant in the country in which they are spoken (such as the Liverpool accent in Britain and the southern accent in the US) are quite appealing to foreigners, since they do not know any of the stereotypes about the people who use them.
Anyway, if it is possible to give opinions on languages for purely aesthetic reasons I would say Chinese first (that is probably what I would think if I knew nothing about any of the countries in which these languages are spoken) and English last (just because when people are speaking English I can understand the awful things they say - but again, that is not the language's fault).
I actually find German to be quite beautiful. Remember that as well as being the language of the Nazis, it is also the language of Mozart, Beethoven and Goethe; the language of some of the most beautiful music and literature ever written.