I have to say I'm quite amazed how stable the Xbox/Gentoox combo is. As of today, the box has been running for 380 days (and counting...). I've had two power outtages, the first after ~100 days and the second after ~200 days. No other problems. The version is "pro" and it runs on a headless, softmodded 1.3 box.
It's not running any real heavy applications, but some of them are really nice to have running 24/7:
Apache (mod_php & mod_svn)
Ventrilo for game voice-coms
Subversion repository for my own programming projects
I don't do many upgrades and I have never run magic. Remember, "whatever works - don't fix it". Since the box is exposed to the internet - and even if only three ports are open - some packages have to be up-to-date due to security reasons, such as iptables, apache, php & openssh. So they are always the most recent and stable version.
Thanx ShALLaX for putting this distro together