I made my first mod for Beta 1.7.3 today. I always wanted the game to show how many mods are loaded.
EDIT: Requires modloader. Put the zip in your mods folder.
EDIT2: Version 1.1, moved list to the Mods and Texture Packs menu.
Made it also list the mod names and set the color to cycle through all the colors in the rainbow!
Edit3: Version 1.2, Improved rainbow by giving each line it's own color.