From what you are describing the 40D makes the most sense. The 5D is great landscape nature and portrait camera, but 3 fps is just to slow for sports. 6.5 fps is decent and I am quite satisfied with it for both indoor and outdoor sports. If you truly want the best of both worlds IMO then the 1DMIII is the way to go but it is $4000 + for a body. The 40D has the newer sensor and processor than the 40D and the low light/high ISO capabilities are very close.

As for glass, if you want reach you need good glass. I guess that translates to Paparazzi glass. A great camera with poor glass will take poor pictures. A fair camera with great glass will do everything the camera is capable of. I have seen some fantastic stuff from an Rebel with good L glass attached. Good glass, taken care of will last a lifetime. For sports you also want fast glass. Hockey, volley ball, basketball etc. is not too easy to shoot with a f3.5 to f5.6 telephoto zoom lens. Just too slow to give you the shutter speeds you need. On the other hand, an f2.8 or faster lens can do wonders indoors. My basketball, volleyball kit is pretty much the 85mm f1.8 and the 135 f2.0L. I have used my 70-200 f2.8L in some indoor venues that have the lighting to allow it, but they are few and far between.

Fast glass has another advantage when it comes to portraits. Fast glass means a shallower depth of field, which translates to bokeh. It is much easier to get pleasing bokeh with a good piece of fast glass.

IS is nice if you need it, but for sports it is not of much use. Fast shutter speeds freeze action. IS lets you hand hold in low light when there is little or no movement by the subjects. The new generation of IS can be helpful when panning such as at an auto race. But for the most part it is not much use for sports. For portraits, a tripod is better than IS. Of course if you are shooting something like a wedding, a tripod is not practical, but for general portrait photography nothing beats a good tripod.

As for the Olympus, I am not a fan of the four thirds system. I shot some of their film cameras a few years ago and they were pretty decent, but the four thirds sensor is just a bit small to me.

Don't overlook Nikon, The new generation of Nikon cameras seem interesting. I shoot Nikon bodies and glass for 30 year when I was shooting film. When I switched to digital I went Canon as I shoot a lot of what you are expressing interest in. If you go with either Canon or Nikon you can hardly go wrong. Not that Sony, Pentax or Olympus don't make decent cameras. But their lens lines and accessories are much more limited than either Canon or Nikon.