Back when I was just getting fed up with D&D I found an interesting set of variant character classes as designed mostly by one poster called Szatany at WotC’s forums. Luckily, the good folk of Campaign builders’ guild have saved them over at their wiki: http://www.thecbg.org/wiki/index.php?title=Ultimate_Classes
I particularly recommend the barbarian. Adventurer is boring. Don’t start by reading it. The classes are probably for edition 3.5, but that doesn’t really matter. I know next to nothing about Pathfinder, but it is supposed to be backwards compatible.
The classes are notable because they embody what is maybe the greatest strength of 3e: One can take just about any ability in the fiction and come up with an interesting representation for it in the mechanics. (Just be careful with the social stuff.) One implication is that they are pretty good inspiration even if one does not play relevant editions of D&D, as long as one is literate in d20.