There is also the matter of ArchiveInvalidation. But just in case you don't want to go and deconstruct an OMOD archive to use with BAIN because it's too much trouble, then just keep Oblivion Mod Manager handy. However you can use a little tool that comes with Wrye Bash called BAIN to install other archive files such as 7z, RAR, and ZIP. Now you don't have to use OMODs all the time, some mods aren't packed in as an OMOD file and are just structured as one, saying that it's ready to be installed as an OMOD. It's fairly easy to install, just click on it and it will promt you to a some options that you can choose depending on your personal preference.
What's an OMOD? An OMOD is an archive that's specifically made for Oblivion Mod Manager.
