A full charge and discharge of a laptop battery is really neither here nor there with modern battery technology. Lithium Polymer batteries, like those used in laptops, don't exhibit the memory effect that plagues NiMh and older batteries (whereby you had to condition the batteries with full charges and discharges to retain the capacity).
However, that being said, a full charge and discharge of your new laptops battery does have one positive effect: it calibrates the battery indicator, which means that your battery reading both in OSX and directly on the battery will be more accurate.
In general use though, it's best to plug your laptop in when you get the reserve power warning.