As great as some adult privileges are, I can't help but lean towards childhood, but that's probably because I had an incredibly normal one.
When I was a kid, sure, there were rules. Lots of them. I couldn't watch horror movies, I couldn't play video games that had something even remotely evil-looking in appearance (19 years after the original Resident Evil's release and ONLY NOW am I playing it for the first time), and I went to bed at 9:15 every night, no exceptions.
But then again, there was stability, and a lack of any true responsibilities. I mean, you had your chores and everything, but I'd take chores over taxes, going to work, and college confusion anytime. What's worse? Emptying the dishwasher, or going to a job you hate with people you can't stand and a boss that could care less and your car broke down on the way there so now that's another big money-soaking problem on your plate and so on?
Life was simple back then. I had homework and a few chores, and other than that I was utterly free. I could eat basically anything in the fridge without worrying about nasty things like weight gain or cholesterol, I could spend the day playing Mario 64, I could go out and explore the woods (until a coyote appeared in there one time and I was thus not allowed to go back in for my own safety but you get the idea).
And Chris had a point about the morals thing. Everything was in black and white as a kid, that's just how they are. They don't understand or become aware of complex issues and questionable ethics until later in life. When you're young, you "know" right from wrong. Stealing is wrong, sharing is right. Cussing is wrong, politeness is right, etc. Even if a lot of it was stupid, you at least wouldn't lay awake at night wondering if you're a terrible person for whatever reason.
Overall, I'd take being innocent over having access to more things as an adult. At least as a kid I never had any humongous periods of depression.