Hmmm....My favorite Aspect is probably Time. It's just awesome being able to time travel.
As for class...Maybe Heir? I like the look for god tier a lot, and they seem to have awesome powers. Using their aspect to protect themselves, and even becoming it is just awesome. Similarly, I think Knight is cool, considering they use their aspect as a weapon, but to protect instead of destroy.
Speaking of destroy, I also like Bard. Prince's are too open and in your face, while bards are sneaky and manipulative, but equally powerful, methinks. If Gamzee is any indication, you just don't mess with the bard. (Although cronus is weaky weaky weak sauce, so it might just be Gamzee you don't mess with)