What is your favorite piece of free software?

Mine is VMWare Player http://www.vmware.com/download/player/
I also like PrimoPDF - it lets me convert anything that can be sent to a printer into the PDF format http://www.primopdf.com/
And VLC for streaming video from your PC http://www.videolan.org/vlc/streaming.html

My favorite peice of free software would probably be AIM because I basically use it everyday to communicate to friends from across the world as well as friends in general. Its like the perfect communication tool that allows you to do productive things in a technical field that requires the use of a computer. AIM has evolved as a program over the years that it now offer many interesting things that allows two people to futher dive into the networking enviroment. For example, I believe that they created cool games that you can connect with the other to play, I remember the good old days of AIM when smileys was a very entertaining way to express one self over the internet. Now aim has elaborated that and created interesting splash effect smileys.

Other free programs that I often find myself frequently using are winamp, which is my primary tool for listening to music. There is not a day where I dont have a playlist up and running throughout a long day of work. Music is the perfect energy drink. Without these programs I feel naked and disoriented throughout the day.

FIREFOX.

I love FireFox. It's actually changed my surfing habits, my computer habits, study methods, etc... It's not just the program, but the open-source mindset and the community around it that benefit to it to make it better. I'm talking about themes, extensions, greasemonkey scripts, etc...

Another great piece of "free software" is Wordpress. I always used Nucleus for blogging, so I was a little impartial and skeptic about Wordpress, but I gave it a spin anyways. What's so great about Wordpress is the same thing I like about FireFox, the open-source, sharing community, themes, plug-ins... that make Wordpress able to become a traffic magnet to be reckoned with.

Other than that, I use Ccleaner on a near daily basis and it's kept my laptop running smooth and problem free for the past year.

I forgot to mention cygwin - it's a set of Windows compatible command line shells and small utilities which enable you to pretend you're in Unix, writing shell scripts.

I have a lot of greate freeware apps (almost everything on my computer is freeware).
Faststone Maxview (to replace the crapy windows gallery viewer which doesn't interpolate a picture when I zoom in)
dbPowerAmp + lame.exe : great tool for encoding MP3
Mercury Messenger: great messenger
Opera: great browser
...

I could continue for a looooong while, but that's probably seen as spamming (it's a very long list )

I also have a lot of favorite free software that I love to use!

GIMP- awesome freeware photoshop-like program that can do a whole lot of stuff, once you get used to it. I usually use it for small editing purposes (cropping, color change, adding text to pictures), and I love it! No need to spend hundreds on commercial products.

Miranda IM- another amazing chat client, so that you don't have to use Yahoo, AIM, MSN and have them running all at the same time.

As mentioned before, Primo PDF is great for creating pdf files. I use this when I want to make it hard for others to just copy and paste my work.

Audacity: a freeware multi track recorder that is customizable. You can record your music if you're an amateur musician, and get some pretty good quality sound.

Openoffice.org- very good word pressor/all in one office suite.

AoA audio extractor: extract audio from video. Very useful if you're recording live music with a camcorder and you want to also make an audio copy.

you can google and find the links to download those.

Besides all the good ideas already posted, a great free program that I found is allSnap (http://www.cs.utoronto.ca/~iheckman/allsnap/). allSnap is basically a program that makes your Windows desktop windows snap to each other. It is certainly far from essential and is only used for the visual experience but it is always one of the first programs that I install.

I have the habit of having many small windows open at the same time so allSnap is great to get them instantly organized and lined up.

hmmm.... this is a really hard question.

I would at first have to say, well i really like firefox...and I use it all the time...

But then....i also use AIM all the time (and that is free as well, ad supported, but free)....

So I don't think I can choose between those two...so i guess i'll have to make it my favorite pieces of free software

I also really like open office, the gimp, inkscape, scribus, netbeans, and probably a lot more...but that is all i can think of at the moment.

I would have said completely different things, but yeah if you think of what you really use the most I am going with:

MSN Messenger: I cannot find a free alternative to this, that connects to the MSN network and has a better look/feel and memory footprint, and also not heaps buggy (like GAIM and things). I use 7.5 personally, as I do not like the Windows Live one and it never used to work for me period.

FireFox: Been using it for a couple of years now, IE is a bit of a pain and Opera never went down well with me, so FF it is.

WMP, MPC and VCL: The three media players I have been using a combination of for years now, if one doesn't work for something, almost always one of the other two will.

I could list quite a few more, but I think that is enough lol, and the primary ones I use very often.

Free? If you mean both in price and in openness: Linux. One big powerhouse and the operating system that powers Astahost and many Fortune 500 Companies worldwide.

xboxrulz