Windows Software

Free stuff everyone could use:

Firefox - tabbed browsing. Get the plugin "all-in-one gestures" for hyperspeed browsing.

The Gimp - The functionality of Photoshop, for amateurs.

Konfabulator - Free widgets for everyone. The weather widget alone is worth it, the rest are silly toys you may enjoy.

Hey, it turns out those are all cross-platform.

Here's some stuff I find useful, you may or may not:

Aqua Dock - looks like the Mac Dock, I like it.

Cygwin - do your UNIX development on Windows, "make" and "gcc" work out of the box, as do many other tools.

Here's a couple fun tools, for the amateur audio/visual studio:

Wax - a video editing program. It looks like Final Cut, but it's free. Also, saves as a flash file for easy web page integration.

Audacity - an audio editor. Probably not as usable as GarageBand (I've never actually seen or used GB, just heard of it), but I was able to instantly record two guitar tracks over each other by hitting record twice and save as an mp3 by hitting save as... Not bad, also free.