Never had a fixed gear so I can't comment on them. During your commute will you be carrying things? Also, like Drew Eckhardt mentioned you want clearance for fenders. The bikes you mentioned don't look like they would provide much room.

For me, commuting bikes should fit a wide variety of tire widths, have room for fenders, and mounting options for racks (rear and/or front). If you are carrying items I think being able to shift gears would be a plus.