Hello Eddie,
Nice to have you drop by. As regards tools that DIY enthusiasts should have, I suggest this earlier post that I made on buying tools:

http://www.diyautoworksng.com/buying-your-first-set-of-tools-for-car-diy/

As it stands I carry a toolbox in my trunk and I have an ELM OBDII scanner (that works with my phone) permanently left in my car. The toolbox contains everything in the image in that post and more. I guess at the end of the day, it just depends on how deep one wants to get involved in DIY repairs and having just enough tools to ensure you can fix any unplanned repairs that come up on the road!