For services, I like sysv-rc-conf
. The default interface is pretty simple, but there is more power hidden.
The biggest advantage for me of debian based has always been the package management. Granted, I don't do anything fancy and can stick with pure Debian Stable branch for my needs... But I've had seemless dist-upgrades on the server from Debian 3.0 to 3.1 to 4.0 with almost no hassle (my desktop had a few things I had to rework).
is a powerful command also for reconfiguring installed packages. Mostly I use it on my desktop for fixing X.
And how can I forget module-assistant
Here's a debian cheat sheet
. Most of these features should also be in Ubuntu.