Great thread here.

The end boss of Super C is so pathetic I don't think I've lost more than 2 lives on him ever

Baby Bowser in Yoshi's Story is a joke, but in Yoshi's Island I thought he was a pretty well rounded boss, it was definately fun figuring out how to beat his first form and then the kick-ass giant form.

A lot of the RPG's end bosses, like most other people said. The exception with RPG end bosses would be Ghaleon, who put up a hell of a fight. I thought Zeromus was very good for a FF end boss.

My idea of the perfect end boss is Mike Tyson/Mr. Dream. He takes every skill from earlier in the game and pushes you to master his attacks before you can beat him. I find that Bowser is a pretty well-thought-out end boss in every Super Mario game I've ever played.

Konami space shooter end-bosses are always a joke, it's like a tradition.