Here are some nice modifications that I found. They usually involve patch (.ppf) files, so I hope you are computer literate and have the correct applications for applying them.
Halo for the PC:
Attention! Any patches that are made to files used on both Single Player and Multiplayer (E.G. sounds.map, bitmaps.map, etc.) may create weird textures and incorrect backgrounds on certain objects. Backup your .map files BEFORE you edit them!
-The Library for Multiplayer by MonoxideC [Includes Nuke Rocket Launcher]
-Assault on the Control Room (AotCR) for Multiplayer by MonoxideC [Includes driveable Pelicans and Wraiths]
-Halo 2 Mod by NiTrOuSoXiDe [Mods too numerous]
All you should have to do it go to Google (http://google.com) and search for these and you should find something of relavance.











