I had barely touched Linux (or a *nix command line) before I started in my current job, ignoring a few months with a little use of the Terminal on my iBook. Since being here though, I have picked up quite a bit as I've gone along. It took a little while to get used to at first, but it's sort of a second nature now - when it comes to some things, at least - to move over to the command line and do what I need to do there. It's very handy when developing software and working with revision control systems just to be able to do what you want by typing a few commands instead of doing it with the mouse through the graphical interface.
Installing new software is a breeze on Kubuntu (as it is on other Linux distributions) - simply type sudo apt-get install [name of software] and it'll do all the work for you. No need to go to a website, download it, unzip it and double click to install.
I needed to start drawing a diagram, so I asked my colleagues for a recommendation. They suggested Dia, so I went off and installed it and had the first cut of the diagram ready to go within half an hour.