In chronological order:
Hand of A'dal, the Immortal, Storm's End.
Cataclysm kind of gets shafted, I guess, but DS titles/mounts were kind of boring the week after I got them and I can't see "Dragonslayer" without thinking of Coach from Survivor. I really should finish up my 100k HKs achievement. I know it doesn't impress any real PvPers but I've been 7k away for like a year now and "of the Horde" is a pretty solid title.