For males I generally go Nord, they look the most 'normal' to me, and for some reason the others don't look as good IMO. Their battlecry ability also comes in handy, especially when I'm cornered and in need of a quick escape. Plus they're good when it comes to one/two handed.
For females, I'd go either Nord or Wood Elf, they look the best to me (Mind you, I use mods that make females look prettier) and the Command Animal power is really helpful, considering my Bosmer character is kind of a huntress, not to mention I can easily turn a pack of wolves against my enemies. And the archery bonus, I always use bows so the Wood Elf is most useful to me.