I use anything I can dual-wield. I actually prefer other weapon types to fist for stuff like cleave and stun chance on hammers, but right now I happen to be using two fists because I just so happened to find two REALLY GOOD ones.
I'd try 2-handers and even was thinking of using them at first to be 'unique' but as I've built my character I've kind of settled in to realizing I'd benefit the most from going dual-wield and focusing on executes and crits.
I'm rocking 2H weapons on my berserker through the 2nd act right now. I typically prefer average speed 2Hers, and recently found a dervish spell to increase attack speed. It's probably not as optimized since there aren't any skills devoted to boost when using 2h, and you're pushing a lot of what would be DEX into STR to meet the requirements to use 2h but I'm enjoying it quite a bit.
At its best, I pumped a bunch of STR, and was able buy/find a blue ~5 levels higher than me. This with some successful enchanting leads you to swing that bad boy and watch all the mobs in front of you just go squish. This along with the debuff roar and uppercut attack makes for some pretty big numbers.
The downside though, is that you're pretty gear dependent. If I could, I would have this as a 2nd or 3rd character, so I'd have the weapons already waiting to be used then trying to refresh the store again and again. I had a bad time in the ice fields of Act 1 dying quite a few times until I found a new blue 2h sword in the store, which changed everything. Also, if you can find the pieces of the Regent set, that has boosted my survivability so much thanks to its increased damage and steal health bonuses, which is a god send to any melee class.