I love the commentary on Starship Troopers, if only for this bit of Verhoeven explaining the effects (from memory):
"Digital...real...digital!...real!...a-a...a GIANT MIN-I-ATURE!"
Also, I always like Val Kilmer as an actor, but his commentary on Spartan indicates he's an intelligent guy - serious about his work, but with a dry, deep, wicked sense of humour.