I'd prefer if (un)installer asked me if I want to keep anything or not. And then do actions accordingly. If I say "Remove everything" it should act like I'm running avast! Uninstall Utility. Leave NOTHING behind. If I decide to leave something behind, do so. It's really annoying that apps leave bunch of crap behind which just ends up being a liability or issue vector later in time, especially when reinstalling because of an issue...