Software management through packages is a killer feature. Not having to hunt down installers and keeping track of what was updated and automagically installing those is pure nirvana.
I use Ubuntu on a Desktop PC, and package management really is a huge win. You pretty much say goodbye to those annoying "Next...Next...Next...Next...Finish." installers. Updating installed packages is generally pretty painless too.
I generally build systems with as little as possible installed initially. Then install exactly what I need. With Ubuntu I can't remember if I ever had to hunt down any dependencies. The security updates are non-intrusive and rarely require reboots. Compared to Windows constant nagging about this, that and whatever it is so clean and painless.