• JuiceDefender - save battery power (lots of it!) by controlling the device data connection and/or WiFi
• SeePU - shows the current CPU, RAM and network utilization in the notification area
• JuicePlotter - a battery usage graph that combines full at-a-glance information about your battery consumption with sheer beauty
• Paperdroid - an offline article reading app that integrates with Read It Later and/or Google Reader.

Get me some caffeine! (and a tiny amount of carbs too)