On the lack of an optical disk drive: I do a lot of business travel and I've never had an optical disk drive. Ever. It's very rarely an issue. Example: if somebody wants to hand you files without emailing them, they use a USB thumbdrive. I think I once had a case where we had a CD that we needed to read and share; one guy with a CDROM read it and then we passed the contents around on a thumbdrive.

On catastrophic failure and the need to reinstall: I figure, if all else fails and I'm in a foreign city, I can always find a nearby Apple store. They'll have everything. (Hopefully.) I am quite curious how you can boot or do disaster recovery over the net. I'm also curious what you're supposed to do if the hard drive fails, since it doesn't appear to be user accessible. Sounds like another reason that you should only buy an Air with the SSD disk.