GamePro got all scientific and decided to test the battery life of the current-gen wireless controllers. As we've learned over the last year, the hidden cost in this generation's consoles is the money spent on batteries and/or charge kits. For GamePro's testing it used only "out-of-the-box hardware" and followed various reasonable rules in its procedures. The results:
PS3: The Sixaxis died after about 19 hours and doesn't have an auto-off feature. The upside is that the controller recharges through USB connection to the console and doesn't require purchasing batteries.
Wii: The Wiimote lasted almost 37 hours, but depending on what games are played the rumble and audio within the controller can drain the battery faster. Although the batteries won't last as long, consider rechargeable batteries or the Nyko Wii-charge Station.
Xbox 360: Lasting almost 57 hours the controller was the winner in the battery life test. Just like the Wii, consider getting the first-party Xbox 360 Quick Charge Kit to save cash in the long run.
All the controllers have their good and bad sides. Although the Sixaxis allows gamers to plug in and charge while playing, for those who have their PS3 more than a few feet from where they actually sit and go on gaming benders, it may be worth investing in a USB extension cable. As for the Wii and Xbox 360, investing in charge kits (or rechargeable batteries) will definitely save cash and avoid the awkward situation of a dead controller with no AA batteries in the house.