Go Genuine
Had a non genuine recharge pack that only lasted 6 months. Bought one of these a few years back and it's still going strong. So now I have 2!!

These things sure last...
I don't want to think how much money I would've spent on normal batteries. Definitely worth the purchase.

No title
Save your money (and earth) from AA batteries...

A must-have
Anyone who has the 360 Wireless Controller needs to get a rechargeable battery pack. If you already own one, it's always a good idea to have a spare. After all, its only 10.90 US dollars!

The Best!
My friend keeps using AA cells in his controllers, which not only are a huge waste of money, but detrimental to the environment as well.

I have always used the rechargeable batteries from Microsoft as they are reasonably priced and give excellent battery life, usually lasting weeks with moderate gaming.

If you purchase only one accessory for your Xbox, make sure its this. And don't forget to get a good external charger as well!