>Get used to not having a disk. That's the way things are going, even more so with Windows 8.
I expect, like Apple's Mac OS X Lion, after you install the file(s), you will be able to create a DVD disc to either install from or also boot from to setup/install the OS. In other words, less software available from companies on disc, but you can create or own setup disc burning a DVD.
I don't know if Windows 8 can be installed from a USB memory card, have you heard if that might be supported?