I've been wanting to do this for a while. There are some great open source products out there that I use on a daily basis, and wanted to make sure people knew existed. There are a bunch of us on here that have a nice collection of free and open source software. I'd like to sticky a list at the top of this forum, so we'll have a reference for people to find good open source projects.
Lets stick to desktop software for now, and we'll do another thread for Open Source server software.
Here are a few off the top of my head. I'll add more later, and list a comparable software if I can think of one. Maybe I'll even be nice and add some links at some point. You have google, use it.
OpenOffice - Office
GIMP - Photoshop/Illustrator
Audacity - Audio/Sound
Pidgin - Instant Messenging
Combined Community Codec Pack (CCCP) - Audio/Video Player
uTorrent - BitTorrent client
ClamWin - Antivirus