Not to start yet another "synthetic vs. regular" debate, you may want to consider using Mobil 1 synthetic ATF. I switched over since my car sits out in the cold while I'm at work, and like synthetic motor oil it doesn't thicken up as much as conventional ATF in the cold. Also runs a bit cooler (they say) in the summer due to decreased friction.
Also, don't forget to drain the torque converter! That's the only tricky part.