I found this website from lifehacker.com and found it really invaluable. Basically SoftwareFor.org is a free collection of programs meant for students and non-students alike to download and use on their PCs or Macs.
For a list of what programs are bundled, you can check out their FAQ page. I’m already using OpenOffice, Firefox, Filezilla and Thunderbird, but there are lots of other cool programs I would totally be interested in trying out, such as Audacity and XAMPP.