no. that applies to nickel based battery tech.
The only reason to let li-ion batteries drain down is to recalibrate the battery life indicator.
Two things kill li-ion batteries like those in laptops and the iPhone, heat/temperature, and deep drain cycles.
I thought this was common knowledge at this point, clearly noted on my laptop manual. Li-ion batteries are designed to last longest with shallow cycles, as in if you could get 100 deep discharge cycles you could get thousands if the battery was never below 50%.
So to recap...charge every night, short drain cycles are good, and keep it out of a hot car (esp a fully charged one).
Battery University is a good place to start. Here is a link so you will know I am not full of shit...but this is well documented all over the place.
All kinds of good tips and info:
http://www.batteryuniversity.com/parttwo-34.htm
The natural degradation of li-ion regardless of use is also why having non user replaceable batteries completely sucks.