Mirage OS	This is a very cool Operating System for the TI-83+.  It organizes your programs, runs Ion and Mirage assembly games, and can be used in conjunction with TI's startup application.  Because it is run from archive, it takes up less memory.  It also can run programs that are archived, leaving more ram open for you.  Plus, the best games we have need this to run anyway.
Ion Shell	This is a shell not quite as good as MirageOS.  I really recommend getting MirageOS (No offense).  It's just that MirageOS runs all the Ion games already.  So why get Ion?  It is here if you want it anyway.
Picture Viewer	This is the first picture viewer that I have found for the TI-83+.  Although all the pictures I have converted with the included bitmap converter have not turned out, it is still worth getting if you want graphics as well as games.
Sound Program	I think this is very cool.  It was the first sound program I got to work on my calculator.  I thought sound through the calculator was a myth, but this and the game timi (in games) proved it true.  I will put on more sound programs as I find them.
Startup Application	This is the application distributed by TI.  It runs a picture, program, or application when the calculator starts.  There are many programs out there made to run in conjunction with this app.  It came on your resource CD if you bought the calculator!!!!!
Encrypter/Decrypter	This program encrypts and decrypts messages and saves them as pictures.  Although a little slow and painstaking,  private information can not be found out unless you know the password.
Asmpass	A password program for your TI-83+.  Make sure you push the right buttons when you enter your password and remember it well, because otherwise you won't get back into your calculator.