content: Well, it depends on what you do. Think about what a typical session for you is like using Windows. Web browsing, built in. Checking email, there's probably a built in email client unless you're using your email's web app. Time wasting games like solitare, checkers, minesweeper...all built in. If you have other things you'd like to do, open up your package manager and start searching for things and install them. You probably have LiberOffice Suite already installed. And there's probably some basic image manipulation program like GIMP or something similar. As far as antivirus, a majority of viruses are made for Windows since it has the largest market share of OS's and people who make viruses want to infect the largest amount of people. Having said that, you might want to have an AV program if for nothing else to prevent you from spreading viruses to Windows machines. This thread from  /v/linux  has some good info and comparisons of AV programs for Linux. As far as general security goes, keeping your system up to date helps a lot. Then there are other things you can do, like this checklist. Some of that is overkill for the average user but it doesn't hurt to learn about it.