Backtrack is platform which is specially crafted and designed for penetration testing. Metasploit is framework that is used to create and experiment with exploits and payloads. Both are must for a hacker today. Alternative to Backtrack is Knoppix Security Edition and Mautrix, if you master Bactrack you’ll easily master both of them. So I will not leave them apart from our list, we’ll also cover them.
Disclaimer : This information is just for educational purpose. If someone use in malicious activity then only he is responsible for it.