BackTrack is actually based in Ubuntu. It is a special-use Linux Distro (special-use = meaning ginagamit ito for specific purpose...this is not designed for general use).
Kumbaga, ang mga *buntu (Ubuntu, Kubuntu, Edubuntu, Xubunty, MythBuntu, Linux Mint, Pinguy OS, Zorin OS, etc. etc.) ay pang general-use. Ang mga tipong gagamit ng BackTrack ay yung mga may specific needs (hackers, Penetration Testers, Information Security Officers, etc.). Kung general-use lang po (surfing the Internet, games, Office apps), hindi kailangang gumamit ng BackTrack.
Pansin ko lang sir, medyo nag-iinquire kayo sa medyo maraming Linux distro. Just to share, there are hundreds of Linux-based distros available. Baka hindi na kayo makapag-try sa kakaisip ng gagamitin.
I would recommend to start with Ubuntu or Linux Mint, to get you started with Linux. Friendly advice lang. Saka na ninyo isipin yung iba pa, once medyo naging proficient na kayo at may specific needs kayo.