This is some what inspired from fable. Chicken kickers. Basic the title would have a different font and maybe a constantly changing color and always be next to your name as long as you desire. To unlock titles one would have to repeat some action or set of actions over and over again to be able to use.
Here are some random idea off the top,
1.Murderer
2.Hunter
3.Merchant
4.Hero
5.Villian
6.Troll
7.King
8.Queen
9.Warrior
10.Theif
11. Barbarian
12.PeaceMaker
13.Immortal