Yeah, just use the title you think sounds coolest or funniest. It's a nice perk. I think I still have "The Outlaw" on my Scoundrel even at end game just because I like it. I'm sure there'll be new titles coming in 2.0, just like TFB brought Red Rhombus and Dreadtooth brought Drouk Hunter.
I've got a lengthy list of titles on my Commando, but the one I wear is "Major"