Firefox 4 is out folks. It's noticably faster, but if installing over the top of FF3, my recommendation is either don't upgrade or if you do upgrade, consider resetting the preferences as the UI is quite different and really requires setting up from scratch to allow you to make the best use of the new features.
Ninite - a simple app to automate the installation and keeping up to date of a set of core applications for Windows or Linux machines. I've tried it to update my current apps and it works exactly as advertised. Brilliant! Great if one reformats and needs to reinstall. The apps available are sane and the core of what most people use, and it doesn't install any toolbars or crapware along with it.
CrashPlan - Where Dropbox (my referral link; gets us both extra free space) is like a (free,) secure, online, omnipresent USB key, CrashPlan is the (free,) secure, mutual automated resumable delta-backup solution you've always wanted. Back up stuff between your own computers. Make arrangements with your friends to back up your compressed, de-duplicated and encrypted stuff to each other's computers for free, and never worry about losing stuff to human error, burglary, fire, flood or failure again! (BTW, yes, I am looking for people to set up mutual backups with - please feel free to ask me)
I'm also looking at SugarSync which is like Dropbox but apparently natively supports transferring other folders and gives you 5GB space for free, but I haven't decided if I like it yet.
UPDATE: Prey - FREE & open-source theft-tracking software for Windows, Mac, Linux, Android. Go get it!