Installing XP without inputing any of the repetitive data like "Time Zone", Computer Name, password. This unattended XP installation Disc I made not only installs XP without inputting the same options over and over again, I also applied tweaks, removed unwanted XP rubbish like 3D Pinball and Solitaire, turned off services and customized my start menu + quick launch without having to lift a finger.
Oh yeah, auto installed Direct X9, Monitor Drivers, NIC drivers, PowerToys, Sun Java. I'm adding to this CD everyday. If I had a DVD+RW, I'd auto install office XP or 2003
