Take back disk space from your e-mail
While the advantage of storing mail locally is that you can access messages at any time -- whether you are connected to the Internet or not -- that also means that, well, all your mail is on your hard drive. Depending on how much e-mail you get, that can add up to quite a bit of space.
Boing Boing posted a great reminder/tip for all Thunderbird users, make sure you run File --> Compact Folders from time to time. You might not save 20 GB like Cory Doctorow, but you can still claim some space.
Outlook 2007 users can save space/clean up their e-mail boxes by selecting Tools --> Mailbox Cleanup. From there you can choose to archive old messages, empty deleted items folders, find messages of a certain age/size and delete duplicate or alternative versions of messages.
When was the last time you cleaned-up your mail program? If you can't remember, now might be a good time to archive old messages and clear out those deleted items.