I'd love some tv and video game inspired hair styles. I really want a Bart Simpson haircut. Heh, or a good spikey haircut to remake cliched blonde rpg heros.
My first thought was that I'd want a style like Goku or Vegeta's from Dragon Ball Z.
I also agree that there needs to be a wider variety of hairstyles. For curly hair, I really want a style similar to actress Melina Kanakaredes. Also a curly up-do would be great. Some half-up, half-down straight/wavy/curly styles would be nice, as well.
@imaGleek- I would love french braids. And a loose french twist or chigon.
As for music and dancing, I completely agree. It drives me nuts when after a wedding, my sims can't have a romantic slow dance.