Essential Apps and Installs for Windows, Chrome, Android

I have a few essential apps and installs that I put on all of my computing devices, including utilities and software. It is also what I install on other people's computers when they ask me to set them up for them. All of these are free.

PC/Laptop/Netbook:
(These are the basics. With these, I can pretty much do 99% of what I need to. Much of what I do is cloud based, but sometimes you need desktop software and apps.)

AVG Antivirus -  protect your computer from viruses and spyware
CCleaner - clean out old and temporary files. Optimize registry.
DeFraggler - defrag and optimize  your hard drive
LibreOffice - free office suite - word processor, spreadsheet, database, presentation, drawing
VLC Media Player - free media player. Plays pretty much every type of video and audio file.
Paint.net - free graphic editing software
Chrome Browser - access all of my cloud services (Google, Discovery Education, Evernote, Tweetdeck, etc)
Chrome Browser extensions: Clip to Evernote, Google Shortcuts - links to all Google services, Goo.gl url shortener, webpage screenshot, Aviary, cloudy calculator, publish web articles to Kindle, Docs viewer, Extended Share for Google+, TweetDeck


Chromebook:
(For me, they sync from my Chrome account)
Access all of my cloud services.
Add Extensions: (same as above)


Mobile Device (Android in my case):
In addition to included apps: (see below for links to lots of Android for education apps)
Evernote, Google Tasks, Google Shortcuts - links to all Google services, Sugarsync, Dropbox, QuickOffice, Amazon Kindle, Pandora, QR Droid, Shopper, Advanced Task Killer, Antivirus/Security, Skitch, Epocrates, Netflix, IMDB, AStro File Manager, PayPal, Angry Birds

Why do schools still pay so much for software? Free alternatives to paid software and services.