This is how a Vampire Robe should look:
http://2.bp.blogspot.com/_TQnzgXCADuc/TSOO-HOL0PI/AAAAAAAAAWw/GIs-sZ9MvC0/s1600/zhentarim.jpg
Tired of robes with like no flow and looking like pajamas, how about something like this:
http://eu.media.blizzard.com/wow/media/artwork/wow-classes/mage13-large.jpg
DA2 had one set of pants and shirt that acted like a robe, but looked a little rogueish
http://i55.tinypic.com/29g0309.jpg
How about some more Armored robes:
http://pt2wiki.gamerkraft.com/images/2/2c/Mage_Set-(Robe).png
And if we do have robes give them some interesting designs:
http://fc05.deviantart.net/fs71/f/2010/089/3/4/3415b3b212a5a9873f8c5e4b29a2419d.png