Some people on the left are upset that Obama hasn't appointed many liberals to his cabinet yet. That's exactly why I voted for him--although some want to label him as a wild liberal, he's generally a pragmatic person who wants to make rational, informed decisions. He doesn't base his choices on party orthodoxy, and he's willing to work with Republicans to get things done.
The fact that Democrats control both Congress and the White House isn't a good thing in my view. There's a real danger that they'll ram through legislation just because they can; the party that's in total power often seems to end up self-destructing through corruption and hubris. Hopefully Obama will be a check on that.