To expand just a little on Roger's advice, Lithium-Ion batteries do not have a "memory" like the old Ni-Cads had. The run-to-shutdown is only to calibrate the charge reporting circuitry, and when you do that, DO NOT force a restart or you can damage the battery. If it shutsdown, recharge fully before using again.
Information from a source called the Battery University (Google if interested), really an industry support group, shows that the optimum use/charge cycle life seems to be in the area of discharge to 50% and then recharge. Repeated deep discharging actually shortens the life of Lithiu-Ion batteries.
Just don't fixate on it, use the iPad and as Roger said, charge as convenient.
Congratulations on getting a new iPad...wonderful device.