I suggest getting this one
http://www.gotmod.com/index.php?acti...Xbox%20Systems
It comes with the new "X-ecutor 2 Lite" modchip. It has an on/off switch, and has xbox live installed.
I dunno if you know this, but if you go on Xbox Live with a modded xbox, you will be banned perminately. An on/off switch is included. This makes it so you can switch it off to go on xbl, then turn it back on when you want to play your backups.