Soldier, heavy weapons expert. Martial Artist, duh. Engineers, build robots to fight for them. Bureaucrat, wheel and deal your way to level 200. There are four races to choose from, all of which are genetically engineered versions of the basic human.
Weapons are widely varied.
There are both energy and projectile guns. Melee weapons like carbon-titanium swords. Armor can be nano-tech enhanced for improved physcial prowess or turn a brute into a walking tank. Much of what I've read about it points to a very Dune-like setting. I read it's possible to achieve level 200 in AO, and that gaining levels is much easier.