Right after I got my E-510 this summer, I went on a trip to SE Oregon to photograph wildlife. I also brought along my E-330 for comparison, and I found that the IS allowed me to take some amazing shots. For example
this one of a great horned owl, taken with the 50-200mm zoom.
I also used the E-510's IS in combination with a Manfrotto monopod, using the 50-200mm lens plus the 1.4x teleconverter, and that worked very well for me,
even in very low light. I would love to see testing done (like you did in the article) using IS with a longer lens along with a monopod.
Here's a 2 second exposure done at night, with the monopod (albeit at 14mm).
I pretty much just leave the IS on all the time, and haven't noticed any problems.
I just received the 2X teleconverter, and will be trying that out with IS and the monopod (I'm leaving for Antarctica next week).
--wm