New Laptop Windows8 - What security?

[le Pingouin]

Windows Defender is okay but you can do (considerably) better: AV-TEST - The Independent IT-Security Institute: Jan/Feb 2013

How many of the licenses will you actually use? Do you need MS Office or would an alternative like Google Docs or OpenOffice/LibreOffice do the job? Do you run software into the ground or upgrade to newer versions every few years?