What other software is essential if you are buying a macbook?

Going to be getting a new laptop for the wife and think we are going to get a macbook. I know nothing about apple software so beyond what comes in the OS what other programs should we look at buying? This is going to be mainly the typical email, internet, and porn user. Some messing around with videos and pics.What other software is essential if you are buying a macbook?iWork or Microsoft Office 2011 are essential if you want to open Word documents, Excel sheets, and Powerpoint presentations.