ideas on use as main OS for my situation?

I have used Ubuntu for about a year or more. I duel booted a laptop and basically never booted that computer into windows again. I am VERY interested in Security, maleware/spyware analysis, pentesting, and forensics. But more as a hobby right now as I am not getting paid for work in any of those fields.

I have basically got to the point that I wanted to reset the laptop to factory settings to either make more space for a Linux partition, or go all the way and make this a Linux only laptop.

Backtrack contains all the tools I want to use and learn about. But I know there are issues with using it as your primary OS since it is not built for that. So I am wondering Should I just keep using Ubuntu since it is the base of BT and just add the tools I want to use as I go? Or should I just make the jump into BT5 as my only Linux OS?

If i was you i would continue using Ubuntu and add tools as you go. You will get a lot more security updates through the official Ubuntu community and will definitely be a more secure option.

Would you not consider running Ubuntu and running BT via VM inside Ubuntu?

I guess I could learn to do that. :o