[cmregado]

I did some careful reading about batteries and found a pretty interesting site. If anyone's interested, here are some excerpts from http://www.batteryuniversity.com/partone-12.htm about charging lithium-ion batteries. Although I'm by no means an expert, I've evaluated to the best of my ability what the important bits mean for us before each quote if you don't want to read it all.

About overcharging: (summary: Simply not possible unless you have a defective and hazardous battery.)

Much attention is focused to avoid over-charging and over-discharging. Commercial lithium ion packs contain a protection circuits that limit the charge voltage to 4.30V/cell, 0.10 volts higher than the voltage threshold of the charger. Temperature sensing disconnects the charge if the cell temperature approaches 90°C (194°F), and a mechanical pressure switch on many cells permanently interrupt the current path if a safe pressure threshold is exceeded. Exceptions are made on some spinel (manganese) packs containing one or two small cells.

The fact that overcharge is not possible because the circuit shuts down when the charge is complete means that "supercharging" the battery for that extra little bit of life is impossible, and also that it should be safe to leave the device plugged in all night long (unless of course the battery is faulty and this safety device fails).

About over-discharging: (summary: Letting the battery die completely permanently damages it. For safety, your Touch's battery indicator is not a true representation of the charge remaining in the battery... more on this later.)

Extreme low voltage must also be prevented. The safety circuit is designed to cut off the current path if the battery is inadvertently discharged below 2.50V/cell. At this voltage, most circuits render the battery unserviceable and a recharge on a regular charger is not possible.
There are several safeguards to prevent excessive discharge. The equipment protects the battery by cutting off when the cell reaches 2.7 to 3.0V/cell. Battery manufacturers ship the batteries with a 40% charge to allow some self-discharge during storage.

About priming: (summary: Well, this is short and self-explanitory...)

Lithium-ion is a very clean system and does not need priming as nickel-based batteries do. The 1st charge is no different to the 5th or the 50th charge. Stickers instructing to charge the battery for 8 hours or more for the first time may be a leftover from the nickel battery days.

About charge readings and more on priming: (summary: There is a digital circuit in the battery that acts as a "smart" charge meter. To prevent complete discharge and the resulting damage, this meter reads 0% before the battery is actually dead. This point is when your device powers off. Back to priming... once again, it's fairly pointless.)

Unlike nickel and lead-based batteries, a new lithium-ion pack does not need cycling through charging and discharging. Priming will make little difference because the maximum capacity of lithium-ion is available right from the beginning. Neither does a full discharge improve the capacity of a faded pack.

The absence of topping and trickle charge also help in simplifying the charger.

The above quotes prove that the technique of waiting until your battery dies, then powering it up a few times to get the battery even lower for a complete recharge is a bad idea. You risk permanent damage to the battery. However...

However, a full discharge/charge will reset the digital circuit of a 'smart' battery to improve the state-of-charge estimation

This means that the near-complete drain technique messes around with the smart meter a little bit, since it's an adaptive device. From what I gather, bringing the actual charge of the battery down lower than what the smart meter had previously set to 0% will set the new actual charge as 0% on the smart meter. While this may slightly improve the time your battery can run without a charge, it is not healthy for the battery and will shorten its lifespan.