OS X was unique when it was released, Apple did not include it with systems until June 2001, and it wasn't the default boot until almost a year later.
I was given a PowerBook G4 500 when I graduated from High School, when we went to pick it up, the salesmen were surprised that it came with OS X, and doubled RAM at no extra cost. I didn't install OS X the first time until July, shortly after I arrived at college. I enjoyed many aspects of the system, except for the inability to run games like Sim City 3000 in Classic Mode, and issues related to attaching TVs via the SVideo connector, not to mention the lack of a DVD player. Between July and the release of 10.1 in September/October, I'd actually had to have my system sent back to Apple 3 times due to screen/Video Card issues. Each time, when they reformatted the hard drive and installed OS X they did it a different time. The first time both OS X and OS9 were on the same partition, in the second, they were separate, and the third, they were separate, and there was another partition for data. After the third time, I reformatted again, and followed the recommended procedure to install OS X and OS 9, including installing OS X first, then installing OS 9 as a New OS. After 10.1 came out, I began booting into OS 9 less and less, until after 10.5 came out, and I was stuck on Tiger, I actually loaded OS 9 onto my iPod and would boot of of it when I needed. Now, there are only two or three things I could think of still wanting OS 9 for, like SC2K or Myst, but nothing that makes or breaks the system. Now that I'm on a machine that runs Leopard, and I don't have the option, and I don't miss it.
I just hope that 10.7 doesn't take us cold turkey away from PPC, a bit faster than we would like.
TEG