I use a Minolta 80-200 2.8 APO on my Sony Alpha A100, I also have a 17-50 2.8 Tamron and the kit 18-70 3.5-4 lens.
My main set up seen here:
I'd personally stay away from Sony and Minolta. The alpha doesn't handle noise well and has a difficult time with sports shots, and the Minolta lens has a really slow and loud autofocus, so I miss a lot of shots from that.
But it's a pretty nice camera don't get me wrong, but it gets annoying at times...