Building a Linux Computer?

[mike enriquez]

I am planing to build a Linux computer.  I have Ubuntu 16.0 on an old 
Dell XPS. I will be using it as my research computer.   So "I will be 
going where where others do not dare to go."  I want a VPN on it because 
I have not been able to install a VPN on the computer I now have. I want 
a 64bit OS.

I know that most people say to use and old computer to run Linux.  I 
need ideas on Hardware to avoid and use.  What would you do if you had 
to build your own Linux computer from scratch?

Thanks for your input.

Mike Enriquez