My absolute favorite text editor is the free
NoteTab Light. I use it constantly, probably more than any other program. It has tabs like Firefox, and a wonderful feature called the Clipbook, which can be used for such simple purposes as pasting in a piece of text you type in frequently, or, you can actually program it to do much more complex tasks using the Clip programming language.
ShortKeys Lite is a handy little program for making shortcut keystrokes for strings of text you type frequently, or the current date/time, etc.
My favorite web browser is
Opera, even though I also use
Firefox and even Internet Explorer 6 at times.
BrowserTraySwitch allows you to quickly and easily switch between your default web browsers. This is useful for such things as quickly and easily making it so that when you double-click on an HTML file, it will open in the default web browser you selected.
UrlHistory - "Watches the clipboard for web addresses and saves them with a comment." Makes it easy to save URLs. There are plenty of other useful little programs on the same page, but I use UrlHistory most often.
For what little audio editing and audio recording I need to do, I use
Audacity.
WinJammer Shareware is the only MIDI software I've found for Windows that I can stand to use.
PKVolume is a little hovering volume bar with which you can easily change the audio volume whenever you want.
Skype is an internet phone service. It's free to call other Skype users. Hopefully it won't crash your computer - I tried to upgrade to the new version but it crashes my computer, and I didn't keep any installers for the old versions, so now I don't have Skype anymore. Fortunately, I never used Skype that much, so, I don't miss it.
Paint.NET is a paint program which I haven't used very much (just haven't had any reason to), but I tried it a while back and remember liking it.
A really fun paint program is
Art Rage 2. It's probably even more fun if, unlike me, you can actually paint well...
POV-Ray - short for "Persistence of Vision Raytracer". I haven't used this very much, since I'm not really into making graphical stuff, but, with this, you can type in some textual source code describing what kind of objects you want displayed and where they should be located, what kind of light source you want and where it should be, etc., and end up with very neat-looking 3D scenes based precisely on what you input.
Celestia - "The free space simulation that lets you explore our universe in three dimensions".
Google Earth, a program where you can zoom around the Earth looking at actual satellite imagery of various places.
Astrolog 5.40 - my favorite free astrology software, at least which is for Windows.
Second Life is a massive multiplayer online virtual world. Basic user accounts are free. It has 3D graphics, nice, intuitive 3D building tools, and its own programming language, LSL (Linden Scripting Language).
Second Life also has its own "virtual" economy, a currency called the Linden $ (L$), which can actually be exchanged for real money. I think Second Life actually has the best instant online payment system currently in existence - better than both PayPal and credit cards, due to the lack of fees on any transaction within Second Life, and the fact that you don't have to worry about chargebacks or a transaction being disputed or anything like that, since all transactions are final (unless I'm mistaken).
Entropia Universe is another massive multiplayer online virtual world, with much nicer graphics than Second Life, but it's not as customizeable (for instance, you can't change your avatar's appearance on a whim), and it's more like a standard roleplaying game. It too has a "virtual" economy. But, sadly, there are big fees if you want to cash out your money, and it's a lot harder to make any money. The most fun thing about EU for me is just walking around taking pictures - the graphics are so great it's not hard to take some really desktop wallpaper-worthy pictures.
Fraps - screenshot software you can use with Second Life and Entropia Universe, and other programs.
Perl, a really useful programming language. The Perl distribution for Windows is called ActivePerl, and it's available as a free download. Even short scripts written in it can do remarkably useful things.
Inform, "a design system for interactive fiction". Another programming language. It's intended for creating text adventure games, but can be used for other purposes.
xampp - "an easy to install Apache distribution containing MySQL, PHP and Perl". Web server software/offline development environment which is useful if you want to develop PHP/MySQL stuff on your own computer without having to upload stuff to your web server to test it. I assume it's probably a good idea to take security precautions when running it whilst connected to the internet, unless you actually want to serve web pages from your computer to the internet.
I also like some things others have mentioned already -
Gimp,
Winamp,
WinRAR, and
Spybot.
Haven't tried or used most of the other programs mentioned but they sound interesting. Thanks, everyone.