You can use a Linux live CD for security on public computers, but there is also another benefit: Linux has thousands of free programs that can replace many of the programs that run on Windows and Mac.

A comprehensive list can be found on the replacements for Windows software on Linux list. I'll highlight some of the best ones here:

Free Graphics Programs

The GIMP

A great replacement for Adobe Photoshop is the the GIMP (GNU Image Manipulation Program). There are many free GIMP tutorials online. There is also a version for Windows called Portable GIMP that you can download to any Windows computer for editing digital photos. The GIMP can do most of what Photoshop can do. Here is a screenshot of the GIMP tools:

Inkscape

If you like to work with vector graphics, try Inkscape. Vector graphics are good for clip art, illustrations, and any kind of image that needs to be resized. An advantage of vector graphics is that they can be resized without losing any image quality. Inkscape comes with a set of excellent tutorials that you can find in the help menu.

F-Spot

F-spot is similar to Google's Picasa (which also runs on Linux). It is a good program for simple editing and organization of your digital photos. Check out the features list for more information.

Web Browsers

There are many Web browsers for Linux. Firefox is the most common one. Another one that you may come across is Konqueror. I prefer Firefox, but Konqueror is a good secure browser that can also be used as an FTP client. Parts of Konqueror were used for Apple's Safari browser.

Office Programs

The most advanced free office suite for Linux is OpenOffice. It is compatible with MS Word, Excel, and Powerpoint. OpenOffice comes on many Linux live CDs. You might also find alternatives like Abiword and K-office.

Instant Messengers

The most popular instant messenger program for Linux is Gaim. It is found on most Linux live CDs. Gaim allows you to log into Yahoo Messenger, MSN Messenger, AIM, ICQ, IRC, and others all at the same time. Another popular instant messenger for Linux with similar features is Kopete.

Email Clients

A great email program that can replace Outlook Express and that runs under Linux is Mozilla Thunderbird. It allows you to check your POP and IMAP email accounts.

Media Players

There are many media players for Linux. My favorite music player is called Amarok. Other options include Juk, Rhythmbox, XMMS, and others.

For video files, I like VLC media player. Other popular movie players are Mplayer, Kaffiene, and Totem, among others.

PDAs

Programs for synching your Palm with a Linux computer include Gnome Pilot and K-Pilot.

Linux Programs

This post is intended to be only an introduction. A more complete list of Linux software can be found here.