Linux at this point has a strange mix of application programs.
If you want graphics applications, you will be overwhelmed with them. Gimp comes free with Linux and is perhaps the finest graphics application available anywhere at any price, it can do some very fancy things and make you look brilliant with very little work. Almost all the graphics here were done with Gimp. However, it is complex and has a steep learning curve, doesn't really do lines and circles and rectangles like you are use to if you use Paintbrush in Windows, and is a pretty big app, so it takes a while to start up. To view graphics use something smaller like the KDE image viewer, or the famous old standby xv. If you want to make boxes or lines or scribble around like you did in Windows Paintbrush, try xpaint. It looks crude, but is far more powerful than Paintbrush. Kpaint is another option here. There is also Electric Eyes, Xfig, Killustrator, Gphoto for your digital camera, KDE and Gnome icon editors, several screen grabbers, xmorph, cad programs, and on and on. And these are just the free apps, there are many commercial Linux graphics apps, like Corel Draw for Linux.
If you want Office type apps you have but one choice, Star Office. It is both the best Linux office suite at this time, and it is free. Kind of hard to argue with that. It is huge, and the interface will seem a little odd at first, (it was designed in Germany) but the other two factors outweigh these two in my opinion. Corel has a new Office suite, but it is version 1.0 for Linux, is a little rough around the edges, and is $100. Other options in this area are: Gnumeric, the Gnome spreadsheet. It is the farthest along of the Gnome Office suite project, is small, fast, and is pretty feature packed, supposedly supporting 95% of Excel features. If you write a lot of letters, look at Word Perfect 8 for Linux. There is a free and a commecial version. It is smaller to launch than Star Office and a very powerful word processor. It is one of my favorite tools. In Mandrake 8.1 Koffice is also coming around nicely.
Plenty of toys. There are many many small free games and many big commercial games. All of the things you need to play on the internet are here, Netscape, RealPlayer, MTV movie player, Java, Napster clients, etc. You can run your own web site if you want, every internet server in the world is included. Apache, the most widely used web server is included, as are ftp servers, pop3 mail servers, news servers, etc., etc., etc.
If you want math, scientific, and other such apps, these also abound, as do tools to write scientific articles, TeX, LaTeX, Lout, Troff, Groff, SGML, etc., etc. These are NOT easy to learn, NOT user friendly, or any other kind of easy or friendly. Window users are advised to steer clear of these for at least two years. They can cause severe brain disorders from just attempting to read the documentation. : )
The same can be said for all the text editors. Although a text editor seems like a simple thing, Linux geeks have turned them into huge appliances like emacs that can cook your dinner while rerouting all your mail through China, but are as big as a battleship and take a doctorate in computer science to operate. Steer clear of ed, elvis, emacs, joe, vi, vim, et al. Stick to something simple like kedit or kwrite.
If you are a geek and like to program or want to try to program, you will be in heaven here. Every possible programing language you have ever heard of (and probably a dozen you haven't) are here, full bore, and free. You can bang away at assembler in the attic or hack away with fortran or cobol or throw together beautiful X window apps in minutes in Glade or Kdevelope, and Borland has a free and a commercial version of their new Kylix programming environment for Linux a well as Jbuilder, or play with perl or tcl or python or whatever.
I've probably forgotten something, there are 7 CDs and over 1000 packages in Mandrake 8.1 : )