The Miami final is always best-of-5 and will probably be that way again this year.
The Indian Wells final was also best-of-5 up to 2001. Then in 2002, it all of a sudden turned into a best-of-3. I suspect it was due to ABC.
And this year, ABC is showing the final again, so it will probably be best-of-3 again.
My faves, for you to bash
Roger Federer, Lleyton Hewitt, Marat Safin, Tommy Haas