I have three possibilities to installing and running Ubuntu as my main operating system.1) Install onto an external SSD: Obviously, this would mean installing onto the External SSD and connecting through USB. I would have my main drive at start up select this driver, if not, it will select the Mac boot up (therefore, I don't have to completely remove OSX). I will also make nightly back-ups of my SSD to another external HD plugged into my main computer. 2) I completely remove OSX and install Ubuntu onto my main machine, use the external SSD to store all the files and libraries needed to carry out my programming duties. I prefer option one since I can take the external HD to work with me and just boot straight into there.I'm just asking for your opinions guys. P.S. Also, I'm running VMWARE at the moment. Can I therefore just use the .iso that I already have? I don't really want to completely re-install Ubuntu as on the VMWARE I have already installed a large number of libraries. 
Ubuntu - Install Options
ubuntu;system installation;dual boot