iLife does not require Classic. You could delete it, I guess, if you want. My impression is that iDVD and Garageband are the elements which consume a lot of space. If you want to delete Garageband (which I think will free up close to 1GB of space), then forum search, because you will need to delete files from the library as well as the application in the Applications directory.
Or perhaps you can use the package file from the install disk to uninstall? Not sure.