I like the Human Female one where it is a bun and two loops.
It's very regal and princessy.

I'm a tom-boy. I like the short hair choices for human female. The ones that go right below the ears. The one with one braid, or with many braids, and the one thats just pushed behind the ears.

I like the one on the Khajiit female with the shoulder length hair, with part of the lengthy hair in a pony tail and a loop in each ear.

I use the short hair styles too - the longer ones tend to clip a lot.

None, they all look hideous, like spaghetti or http://4.bp.blogspot.com/-1yvvJ9eCH5U/TrkXAGyOz4I/AAAAAAAAA1Q/NI_FGL9b-9g/s1600/The-Elder-Scrolls-V-Skyrim-Ranger-Hunting1.jpg
Thanks God there are hair mods, or I'd have to wear helmets all the time.

I prefer the one with two braids and the hair pushed back. (The one in my avatar)

Really it depends on the type of character I'm playing, but one of my favorites is the unisix twin-braid style that Jarl Balgruuf wears.

The one that Jordis the Sword-Maiden has. Long on both sides, with a slight "arch" above the forehead.