i don't personally believe mark's statement, but you can take that
you won't run out your battery life anytime in the next 5 years or more, and i doubt you'll still have the phone at that time in your life. so just charge it up for 10+ hours (or how many ever are recommended by RIM) and then just be happy afterwards. i honestly think that fully discharging the Li-on batteries is a bad thing to do, but thats my personal opinion based on my research of the subject matter.