I have both the 135mm f2 and version 1 of the 70-200mm f2.8 IS and most of the time will opt for the latter due to reach, diversity of a zoom and also IS. If you can get fast enough shutter speeds then the 135 is great but in many situation I would rather lose a stop and be able to use IS. To hand hold the 135 on a crop body I would say you need to be in the 1/200 - 1/320 shutter speed range (depending on how stable you shoot) so that will involve pushing the ISO quite a bit.
Similar situation with the f4 version of the 70-200, you are regularly going to be scraping some very low shutter speeds so even with IS, if someone moves that will blur the photo.
