[criddell]

Yeah, you really do need more information to decide if that's fair or not.

I don't really see a problem with tax brackets though (I'd rather see a formula though rather than discrete ranges).

I'd argue that a lower income bound and upper taxation rate should be established - say $20,000 and 60%. That means that no person earning less than the lower bound will be taxed and no person will pay more than the upper bound in taxes. Then it's just a matter of describing a curve that satisfies those two constraints.