I voted for "Paladin" and also "No Classes". I should have voted "Assassin" too, but hit submit in haste.
Anyway, let me explain:
I really dislike 4e's Paladins. For me, the defining characteristic of that class is the behaviour restrictions, and removing those kills the class stone dead. And it's not enough to say "well, you can play your character that way if you want..."; without the
restriction it just doesn't work.
So, if Paladins are included in the game, then so too should the alignment system be included, and the Paladin should be LG-only.
If alignment is not part of the game, the Paladin should likewise be removed from the game.
And if, as would actually be my ideal, alignment was an optional module, then the Paladin should be presented as part of that same module, and should be LG-only.
(With Assassins, it's slightly looser. If Assassins are in the game
and alignment is in the game,
then Assassins should be Evil-only. But the Assassin, unlike the Paladin, still works even without alignment being part of the game. And for any other class, I'm quite happy to see the alignment restrictions go.)
All of this is IMO, of course.