can you guys say, WHY you think that he/she/it have the most cool design?
Fair enough, I like Lich because he looks menacing without being a conglomorate of weirdness and strange things. I mean, he's a freaking Skeleton wearing robes! The original version looks like he's erupting out of a pile of purple flames, which I thought was awesome. No other boss, to me has given as much in terms of evil without a care for pathetic human life. This is by looks mostly, but also because I play D&D, and having read the Monster Manual entry about Liches I've developed a bit of a liking for them.

Lich looks to be the ... richest of the bosses, I guess you could say.