What a bunch of prima donna reviews. The world isn't going to hand you a beautiful life on a silver platter. College is what you make of it no matter where you go--and Berkeley is no different. There is a very distinct vibe here: intelligent, liberal, politically conscious--but it's not overwhelming unless you want it to be. People are very accepting and friendly. Sure, at first it may seem anti-social, since there are a lot of people who just want to study. If you look, you will find tons of friendly people (it's really not that hard).
If you want something, make it happen. If you want to be social, go greek. If you want quiet life, live north of campus. If you want small classes, wait until upper division (true for any big public university). Berkeley won't hold your hand and I'm glad they don't. Plan your schedule intelligently, and use your phase I of Telebears (registration) very carefully.
Keep in mind that Berkeley is an urban setting, it's safe for the most part, but it's still urban. There are lots of homeless people living on telegraph and all around. There are lots of interesting hole-in-the-wall places to eat--explore. If you want a more "neighborhood" feeling, take BART out to pleasant hill or walnut creek. SF is also just a BART ride away.
Remember--Berkeley, like ANY college, will be what YOU make of it--and there are lots of opportunities at Berkeley to mold it to what you want.