Some character concepts work best with human characters, but some are better with other races, and some arevery race-specific. I like playing human characters, but I don't prefer it to any of the other standard races or their Core Rules sub-races.
Am I the only species in creation that doesn't thrive on conflict? -- Pa'u Zotoh Zhaan
For the most part, yes, though I do enjoy the occasional weird thing. Recently, however, I've been diggin' the Halfling. I'm not sure why though. Of the five games I play in, I have 3 Humans and 2 Halflings.
I'm with Umbran on this one, I'm not opposed to playing humans, but play other races as often. It's rare that I'll play a gnome, but I don't know why. They just don't seem to feature in my thought process when making a character.
This one is a tough one to answer, but I went with no.
Why its tough is that sometimes race is a secondary consideration, and the human feats and skill points add some needed flexibility in getting what I want out of the character. So I said no. I don't necessarily prefer humans per se. I do prefer bonus feats at first level.
Unless I'm going for a class or concept that absolutely demands a demihuman, I'll go with the human. As has been mentioned, the extra feat, skill points, Favored Class: Any are just too nice to pass up, on the whole.