Way back (2000? 2001?) when I was solely a windows guy, a friend was helping me install a linux box (showeq...). I can't remember the distro he used, but I do remember starting from an old windows box and installing linux, installing the applications and so forth. Two hours into playing with the new system, my friend asked if I'd noticed how many times we'd rebooted during the installation and setup - none. We installed from scratch to a functioning system without ever rebooting.
Of course, you want a reboot with any major upgrade to make sure that your system works from a cold start, but it was very cool at the time to have a working system from scratch with no reboot...