I just got a new laptop, and figured I should collate some useful links while my memory is still fresh. Feel free to add your own suggestions...
* Dropbox to sync and backup important files / documents. (Sign up with this referral link to get bonus space for you and me both.)
* MS Security Essentials - best free and lightweight antivirus / anti-malware protection.
* Secunia PSI - automatically keeps track of when your software needs updating.
* Chrome browser will sync in all your old bookmarks and extensions.
-- Make sure you have LastPass, Adblock Plus, and Mail Checker Plus for Gmail. I like the google calendar button too.
-- Cloudmagic (for faster gmail searching) may need to be installed separately
-- as does Google video chat
Office & Productivity
* LibreOffice (the successor of OpenOffice)
* For LaTeX users: MikTeX base, TeXnicCenter editor, and JabRef reference manager.
* PhraseExpress text expansion (based on Lifehacker's recommendation - I haven't yet used it myself)
* F.lux - reddens screen at night to avoid eyestrain & insomnia
* Dungeon Crawl (the greatest game ever)
* Ubuntu (with further recommendations here)
What would you add to this list?