Hmm... this is a tough one. My favorite generic class would probably be Monk, but Samurai and Geomancer come quite close. I like to use Monks because they are quite cheap to use, not having to use one-time-only equipment to be at their strongest. A simple Power Sleeve, Bracer, and Ribbon (If female) does them nicely. They do have low HP (Unless you're talking about Reis), but most foes don't survive a Monk with Two Swords long enough to even put a scratch on them.

My favorite special class is Holy Knight. Yeah their not as powerful as say, Orlandu or Dycedarg, but they serve nicely.