By far, my most used Lens for Video is the Canon EF50mm 1.4 USM, partly 'cause it's been my only lens for quite a while besides the old kit lens (which is completely unusable for video). The Focus ring travels quite a distance, it feels like almost 180˚. This is my first choice indoors with low light.
Second is the 24-105L. I don't own it, but I rented it several times for video projects. It's been a good versatile lens due to its wide range of focal lengths, and IS. For now, I'm trying out the 17-55 2.8 IS on a Crop body.
With a good tripod the 70-200 2.8 L IS is my absolute favorite lens - both video and stills. The focus ring is smooth as butter, there is enough travel to focus accurately. For planned shots, the focus ring is also wide enough to stick a tape on it and on the barrel in front of it for focus marks while still having enough of the ring for grabbing the rubber.