Monk is the most versatile i feel like. you can go look at quin69 for his guides and commentary. He is very experienced player when it comes to D3. I personally have a monk using his build (Sunwukos) and i can solo GR80+ from it. I am no where as good as him when it comes to micro managing and how to play D3 as he solo either GR99 or 100 from using sunwukos and ulianas. you'll understand the builds and stuff from his videos. I hope i made it a bit easier to choose. and also monks can be a support monk as well. Which is really over powered when you have a seasoned player that is playing the damage portion and have like 3 supports just there making sure everyone is not dead and the mobs are clumped.