I prefer the bladedancer sublcass of the Hunter. Although the jump isn't as good, the invisibility is handy.
Titan is the "Master Chief" of the series, and Warlock is the Jedi Master(Especially with the new "force lightning" in the new sub class).
Each has serious strengths(The ability to resurrect with the Warlock is very handy, especially in Nightfalls), but it's all about what you prefer.
I have all three characters, and would never stick to just one.
In my opinion(and with the very welcome advice from Rory and others in this thread), start all three, and get to levelling them all up.
It will be a real grind though. Just remember that you can use your motes of light to level your characters and weapons up now.