For the record, Forbes isn't much better if that happened to be her choice IMO. It's really just a difference between what sort of far-right wing whack job you prefer.
Well, it does sort of depend on which election cycle we're talking about. Forbes was kind of the Mitt Romney of the 1990s. Back in 1996, I'm not sure if he could be said to support any "far-right" policies other than the flat tax (if that counts). His campaign was purely about economic issues, and he completely deemphasized social issues (and was in fact pro-choice on abortion). Then, in between the 1996 and 2000 cycles, he had a disingenuous-seeming conversion on abortions and other social issues, and moved well to the right.
I thought he was just another right-wing hack who compared abortion to slavery. Anyways, Forbes was simply right-wing and Buchanan is far-right. I mean, one is basically a fascist and the other one, though being super-rich isn't a bad thing, is homicidally greedy.