[trebleshot]

Zombie Spawn tops my list as the best. He was just such a cool figure, and I loved how they actually sculpted in a holster for the shotgun. I also really liked Mandarin Spawn, but he was pretty much a plastic statue. A beautifully detailed statue, but a statue nonetheless.

Oh and a couple others for your consideration:

Battleclad Spawn


From series 6, he was one of the most posable Spawn figures I owned and his armor was removable, giving you much more playability since you could pretend he "suited up" for battle.

Hatchet


From Series 13: Curse of the Spawn I, this guy give Cenobytes a run for their money. One of the most gruesome sculpts I've seen and extremely detailed down to the face masks on his hips.