Currently I have a Bester 1200 and Arashiyama 6000, which I follow with a leather strop loaded with 1 micron boron carbide paste. The jump between stones isn't terrible, but sometimes I wish for a "bridge" stone or just something a little finer than the Bester as a stopping point. I hear great things about the Gesshin 2000, but that's almost double what I'd like to spend.
Perhaps the Suehiro Rika 5000? I read that people think it cuts like a 3000.
I was going to get the Naniwa Aotoshi "green brick", but then I found this thread: http://www.kitchenknifeforums.com/sh...Naniwa-Aotoshi
and that made me reconsider.