These free tools have proven themselves for me and my clients. I hope you find them useful:

ActiveWords My favorite time saver - navigate, open, search using text vs mouse-miles traveled. I especially like the text substitution and integration with my Notes mail client. Check out this video on using activeWords to save time with Google/Gmail

Ninite – An easy way to get a bunch of free tools and install them all at once.

Ccleaner – Originally Crap Cleaner for windows

Search Everything – superfast file finder

Auslogics – Disk defragmenter (dont use on SSD disks)

FastStone Image Viewer 5.1 Freeware