Any opinions on what the best software to convert video files to .avi would be? I need to get this video down to a manageable size to be able to put it up on the internet and Final Cut's Quicktime Conversion isn't getting it small enough. Thanks!

I don't think you should consider a .avi file as your best solution.

Actually, Window Media files are pretty decent these days. If you have a Windows computer, Movie Maker is likely on your system, and will convert to various levels of .wmv files.