1. vi or emacs
2. APT or yum or RPM or portage
3. Debian or BSD or Red Hat.
4. KDE or Gnome or flux/black/open-box.
5. Easy to install or get kicked in crotch.
6. Functionality or “my distro only uses 50mb” or obscure.
7. Planned release cycles or whenever they get around to it.
8. You can be a 100% open source zealot or “I can’t live without youtube, dvd playback and mp3s.”
9. My filesystem is better than yours: ext2 or ext3 or JFS or ReiserFS or XFS or NTFS.
10. Amarok or Banshee or Songbird or MOC.