It was a long internal battle between the choices, 85mm or 100mm. Finally 85mm has won after burning a hole in the pocket.
Nevertheless it is just 3 degree difference between 85mm and 100mm in terms of field-of-view, but 100mm is on less expensive side.
Other day, 135mm f/2.8 zuiko was offered for euro 40 in e-bay and cannot afford to deny it.
I'm surprised no-one's really spoken up for Pentax. Their Super Takumar and Limited series lenses are very fine indeed and some of the K, M and A series are not far behind. There are still 50mm f1.2 examples around and the 50mm M f1.4 is abundant and cheap. Any Pentax lens of any era will fit any K mount body, up to and including all digital models (with an adapter for the screw mounts, readily available, and of course you won't get full functionality from a digital era lens on a film body). Pro level bodies such as the MX can be had for under $100. True, there isn't much of a range above 300mm, but if that's not a requirement you might find a decent Pentax kit will leave you some change out of your $400.
Another to consider, if you don't need a squillion lenses, is the Topcon RE2. I had one for 20-odd years and it never skipped a beat. The lenses were peerless, the body indestructible. I wish I hadn't sold it.