Frank Zappa
But as others have said its far to tricky to say who is/was the "best" but I love to see peoples opinions and look up people I have not herd of before.
Some others that are less known (possibly)
Hugh Cornwal (Stranglers)
Capitan Sensible (The Damned)
Im showing my age now lol!!
Im a big fan of Dean Weens work with Ween as well, some of the country inspired stuff is well worth a listen.
T