I tried Dr. Mundo and he was a really unique champion. No mana bar, and you actually try to stay at low health to maximize your damage. It's a balance between staying low to boost your E skill, and not dying. I found myself actually turning on W when I spawn so that I was already low health when I got to the battle.
So what are some good ways to build and play Dr. Mundo? What runes should I stack? I've got health runes in there, was thinking max health so that I could have a low percentage but still lots of health. Regen might be better though?