The argument against leaving optical drive at home when you travel strikes me as questionable. It's only fairly recently that we could burn backups to CD from laptops anyhow. Thanks to thumb-drives, we have more compact options for backup of work files; with an iPod, one could carry a complete hard-drive mirror. ( Of course, you'd have to carry that iPod too--which some people might do anyhow, and some might not.) If you can get online, you can post your work files to a remote location.

I've never needed to reinstall any software from discs when on the road (and a good thing, since I never carry them). I could manage with an ultralight.