A Better Browser
The problem I face most often when trying to show someone a new powerful open source tool is that they just can't believe that the things I tell them are possible. Microsoft has had such a vice grip on the everyday computer experience that it's akin to telling someone that while they've been walking their whole life, it's actually possible for them -- for anyone -- to leap up and start flying like Superman. At the end of the day, it's just not within our conceptual limits to get that that's possible without seeing it and experiencing it.
That's why I implore you to take a moment and go download Flock right now, go through the installation process (you'll need administrative privileges, but they're working on fixing that!), and give it a twirl. Come back later, once you've learned to fly.