[texhax] how to draw chemical structure?

[anhnmncb]

hi, list:
What's the best method of drawing chemical structures for latex?
MetaPost? I didn't search out that it's up to do that.
PPCHTeX? Seems I have to learn context, but I think firstthing I must to learn is 
latex ...
xymtex? Not a good choice.
Now I have to do it thru ``chemdraw -> export xxx.png ->
includegraphic{xxx.png}'' ...

Any advice or indicator will be appreciate.
Thank you.