I think Ke$ha will surprise everybody.
Listen to her demos, man. Read her interviews. It should be patently obvious to anyone with even a modicum of intelligence that there's a lot more to her than what her singles -- or even album tracks -- would have you believe. She's a smart woman and a fairly gifted musician who knows what she's doing. I think she
wants most people to have mixed feelings towards her and to count her out and think of her as someone who probably won't be able to stick around. I think it's kinda dumb for an artist who wants a lasting career to put everything on the table from the get-go. Because once the public has seen it all, they think, "Oh, I'm bored with that. Who's next?" With Ke$ha, though, it's an unveiling process -- she may be starting her career off with (****ing brilliant, might I add) "no-brainer" pop music, but this isn't all she's capable of. I think she's definitely got a few tricks up her sleeve.
And the fact that the public at large don't expect a whole lot from her is actually a really good thing imo. It means that she can always surprise them.

Plus, she has the luxury of not having to meet as many expectations with her future offerings as the other artists listed -- ergo, she doesn't have to play the part of America's sweetheart.