I always like to drain the battery completely when first getting a new laptop and then charge it. No real reason behind it for me but it's just something that i like to do.
It's a lithium ion battery. It doesn't have a 'memory' and can be charged/discharged at will w/o any real ill effects to the battery or it's life. They are also perfectly safe to discard in any ol' regular waste facility. Although I'm sure it's better to recycle. Other than trying to avoid a complete discharge you really don't need to think about it much at all.