Kali Linux 1.0.9a x32/x64 (Former BackTrack) | 2.93 GB/2.84 GBFrom the creators of BackTrack comes...
So, what's the difference between BackTrack and Kali? you might be asking. Unfortunately for us, that's not a simple question to answer. It's a mix between "everything" and "not much", depending on how you used BackTrack.
From an end user perspective, the most obvious change would be the switch to Debian...