Oblivion changing the menu music
From Nexus Wiki
To all who are interested, I'm going to teach you how to change the Oblivion menu music. Thankfully, it's not difficult.
First, go to your Oblivion\Data directory. ie: C:\Program Files\Bethesda Softworks\Oblivion\Data
Then click on the Music folder. In the Music folder, there should be a folder named Special. Open it.
You should see a file named "tes4title.mp3" inside. This is the menu music. I'd back this up first before changing it.
Now, minimize the window and find whatever file you want to use as the new menu music.
Once you have the file you want, copy it into the Oblivion\Data\Music\Special folder. Then rename it to "tes4title.mp3"
Now your music should be changed! If you ever want to change it back, just replace the file with the original.