As I was installing Windows codename “Longhorn” build 4074, I noticed that my computer was displaying a message: (sorry if the wording isn't exact. It's at least very close)

“Feel free to do something else or leave. Just come back in about 10 minutes.”

I love this! After installing six different OS versions / types on virtual PC's, I could never remember if the next step would just chug along for 30 minutes, or ask for two more button clicks in about 2 minutes.  If I guessed wrong one way, I was chained to my computer for no reason.  Guessing wrong the other would mean that the install would be paused the whole time I was gone, making me wait yet again for it to finish installing.   Now, I just wait for it to tell me to leave, and when to come back.  Cool.  Now, if only it would give me accurate information....

I know it seems simple, but I really do like the “All info gathering up front, then complete“ model... as well as the “tell the user it's okay to split“ philosophy.  I hope it catches on with other installations.  Installing FreeBSD was not nearly as fun. (is this going to take 30 minutes? 2? how many more steps are there?)