ONe would think this would help the reporting server loads too.  One form continaing - Date range - Metrics - Trended Ranked - Filter ... would reduce most of my access from 4-5 Submit Button clicks/Server refreshes, to just 1.

I would think a drop-down may not be the best interface. Perhaps a pop up window with scrolling contet.  Along with a checkbox for the segment selection, you could also show the user that created it, as well as comments and some details about the segment create rules and variables.

Pretty basic UI - always show what's being edited.