Like many here, I just take the center of the left turn lane. I generally wait more for cars than cars wait for me. If I happen to take the turn slower than someone in a car behind me, that's just not terribly important to me.
That said, if I'm riding something nicer than my town bike (one-speed, very low gear) and I see that the light is going to change to green as I approach, I have no problem with doing a bit of lane splitting to get near the front of the queue. This is assuming I am familiar enough with the intersection that I know I have a safe place to be after the turn is made.