What makes a word beautiful?

Aesthetics
Carouse - To party hearty; celebrate and jubilate
Coffee
Flaneur - A soulful urban wanderer.
Ramble 
Smirk
Sub Rosa - Under the rose, confidential, secret.
Voluptuous
Zenith

In this article by the huffington post: http://www.huffingtonpost.com/phil-cousineau/beautiful-words_b_2077755.html?utm_hp_ref=books#slide=more261269, some random writer picked out what he believed to be the nine most beautiful words in the English language. Now, while I like these words, not all of them strike me as the most beautiful words ever. What makes a word beautiful? If I had to come up with criteria, it would be:

1. It has to flow well (this one is kind of hard to define, but each person will have their own definition of flow and each person will have their own 9 words)
2. It has to be easy to pronounce
3. Lots of vowels and not too many consonants (this might be because I sing, and vowel-y words are prettier)
4. It doesn't necessarily have to mean something beautiful or great, but if by definition it is gross or dark, it should be crossed off the list on principle.
5. It shouldn't be extremely short (an) or obnoxiously long (perfidiousness), but just right (like Goldilocks? I guess?). Extremely long words are fun, but most of the time they have too many syllables to be really beautiful.

So, here's my list:

Lovely
Illusion
Rose
Iridescent
Cascade
Beheld
Complete
Lullabye

These aren't perfect, but what do you all think? Any criteria I missed out on? Any words you'd like to add to the list?