[quote name='thrustbucket']Care to explain why?[/quote]
I don't know a whole lot of details about what each of them support, but what I know I don't particularly like.
In general (so all of this won't apply to all of them equally), their opposition to immigration and working with other countries seems far too paranoid and damn near xenophobic. I know both Paul and Baldwin are against abortion rights as well (I assume Barr isn't, being libertarian), which I think is a mistake. In general I think they're too against the government, I don't think the government should own or control everything, but I think that a blanket opposition to the federal government really doing anything isn't a good idea either. I'm not a huge states' rights supporter, I think a lot of things are better done on a national scale (and I don't think state governments are any less bureaucratic, in the negative sense).
If you want to list off shit I could tell you what I would/wouldn't support, but in general I'm pretty much a lefty, so I think it's probably obvious why I wouldn't support the more right-leaning candidates.