Here's the Top 10 (and they're all either free or free to Goldsmiths academics):
- del.icio.us (online bookmarking - in my opinion Diigo is much better though)
- The Firefox browser
- Google Reader (gives an overview of article titles from news and journal sites you sign up to - no more bitty email alerts)
- Skype - online telephony and video conferencing, good for e.g. supervision sessions at a distance
- Google search engine
- Wordpress - the open source blogging application, which you can either host yourself or use hosted for free.
- PowerPoint
- Googlemail (aka Gmail) email which organises your email radically differently - by thread as well as chronology
- Audacity - the open source sound editor and recorder, good for desktop podcasting.
- Blogger, Google's blogging tool