What should I do now?

Now that I've beaten the game, gotten all of the skills I need and most that I want, played through most of the UW and FoW, I need something to do. Is there anything that I can do in PvE, that doesn't take several hours (UW and FoW), but is still new and fun?

not in pve.. get yourself and your guild into some good pvp habits, it'll pay off later.

You can go back and Share your Skills and Knowledge with newer more ignorant players. Teach them the correct,polite,smart,etc way to play the game. I have made many "Runs" for less experienced players. I always instruct them to pass it on when they get better and more powerful. Never hurts to give, makes receiving that much more rewardfull.

Try going outside into The Big Room and Talking To People ™

start a necro, if you're a necro, start a warrior.

I've beaten the game three times, as monks. Now I'm making a warrior, and I PvP with 2 of the monks and an air ele. In 2 days I have 50 fame, is this slow or good?

Depending on how often you play, probably fairly slow...