Lithium-ion batteries do not need to go through regular discharge/recharge cycles like the old nicads. They actually get slightly better life if they are charged often, though the difference isn't likely to be enough to go to the trouble. At least not on a device that you will probably only use for two to three years.
When the documentation refers to charge cycles, it does not mean each time you plug the device in. It is referring to how many times the batter goes through a 100% of it's capacity. For instance, if you ran the iPad down to 50% each day and then recharged at night you would only be using one charge cycle in two days.
The iPad's battery is rated at 1000 cycles, after which it should retain 80% of it's original capacity. That's almost three years, and the battery should still have enough capacity for over 7 hours of normal use. (We iPad users are so spoiled that acutely sound bad, doesn't it. A year ago that was pretty decent for a netbook, let alone a laptop.)
Of course, batteries do go bad for reasons other than charge cycles. YMMV
