I love special features on DVD's, I watch and listen to them all. The movie would have to be at least half decent for me to buy it for the special features though.
Also, I do wish some would be what they actually claim to be - like "bloopers" that's 4 minutes of a jaunty tune and people laughing, but you have no idea what they're laughing at!! Show us the c**k-up!!
I don't even mind, and sometimes really like, features on the building of sets, etc. I don't just want to hear how much lead actor likes director and vice versa.