Angus:
Yes indeed, the bokeh with the Olympus 50-200mm is very good. The
lens has 9 aperture blades.
I was seriously considering it, but got swayed by the response form
the new Canon 70-200 f4L IS. I had the former non-IS version, which
took excellent photos - when the lens was steady. And this was why
I sold it, and this is my main problem with the Olympus - no IS. I
would put the 70-200 on my 20D and walk around our grounds taking
dozens of pictures, hoping for one or two keepers. The long lens
(not just mm but physical length) makes it easy to shake. To ensure
sharp photos on these you have to shoot at 300 or 400,
respectively, taking in the multiplier.
If I do get the 5D, the 24-70, 70-200, and a 1.4 convertor will do
it for me - I also have an 85 1.8. For the L1, I keep the "kit
lens". What is really needed is an affordable 35 or 50mm fast prime
for the 4/3 system. (The new Leica lens has got to be expensive - I
haven't seen a price on it yet.)
(And you know I am holding on to my LC1!)
-ddog