As someone upthread offered, I would also recommend to anyone who's getting bored... if there's a class you haven't played yet, get to it. Get the heck out of Hell/Inferno or wherever you're currently mired, and breathe some fresh air.
That's the underlying problem with diablo 3's long term playability imho. It's a console game . You play thru it 3-4 times each time with a different class to experience it with the different class abilities. But once you've done that, what's the point of going thru again with another DH or barb? To try a different gender??
Much as I am enjoying D3, it's appeal is very short term. Once I get a barb/sorc/DH to level 60, it's probably all over for myself as well. Hence why I don't have a problem with the "taint" from the AH. Because ultimately, this game is only called Diablo 3. Just like somebody who's name is the same as a famous rock star/actor. Same name, but they suck as an actor/singer. This game is fun, but it sucks as a Diablo sequel.