One thing that Macbooks could do with is a more advanced sleep and hibernation system that gives you more control over when your Mac sleeps.
SmartSleep aims to do this via a preference pane with four options - Sleep and hibernate, Sleep only, Hibernate only, and Smart sleep. There are important differences between each state. Sleep allows your machine to go to sleep only but it saves the current state in RAM only due to the battery. Sleep and hibernate allows your machine to both sleep and hibernate (obviously).
Hibernate means only your machine will hibernate and the current state is saved on disk so the battery will not be used. Finally, Smart sleep puts your Macbook to sleep and hibernate only once your battery has dropped to a certain level. SmartSleep is easy to use but note you'll need your administrator password to install it because it installs as a preference pane.
If you've found your Mac lacking in the hibernation stakes then SmartSleep offers far more control.