Macro Lenses

Now I've got my DSLR, but now I need a good macro lens, all around similar price points. I've got a few in mind but I don't know what to get?

Sony DT 30mm F2.8

Minolta 50mm F2.8

Minolta 100mm F2.8

Tamron 60mm F2

Tamron 90mm F2.8

Which would be the best? Does anyone have any experience with either of these lenses?