It depends on the character, but I try to match the title to the fashion.

• My warrior is from Elona, so she has had “Elonian Envoy” ever since PoF came out.
• My mesmer has “Freebooter” since he’s rocking a pirate council like suit and eyepatch.
• My asura ele has “Honors in Applied Jumping”, since that’s my SAB character.
• I forgot the exact title, but my raven shaman norn scourge has a raven themed title.

Not sure about the others, but they follow similar trends.