I don't know that there's a lot of difference in what one you get for still photography. I think they all pivot and anything taller than a foot should be collapsible (I like my tall one since I can use it tall or collapsed).
There's only one feature that one of my tripods has that the other doesn't that is worth mentioning, it's that the screw in part is detachable--"Quick Release".
It screws into the camera and it is separate from the tripod. There's a little lever you push and the detachable part snaps onto the tripod--so it's easy-on easy-off the tripod. That way I can leave the tripod at the photo shoot spot while quickly taking the camera off to upload on the computer to see if the pics or good or if I need to start again. :)
The end of this video shows it pretty close up--hard to describe:
http://www.youtube.com/watch?v=I7ho2Lh94g0