Nikon and Canon have the best new lens selection. They are the easiest to aquire as well at least where I am (I don't even know where I would buy a Sony or other around here...) But, Sony bought out Minolta and it will mount any old Minolta lenses you could find on the used marken, as far as I know.
My own personal view which has nothing really to do with specifically Sony dSLR cameras is, I will never buy another Sony product after my experiences with their audio equipment. I still have my 1991 trunk mount CD 10-disc changer that still works flawlessly, but every other Sony product I've purchased or used has been garbage (several portable radios, expensive auto head unit, personal CD players, and a single digital P&S camera.) I now boycott Sony and it doesn't matter what others will say, I won't ever buy again.