I love addons. I absolutely love them. UI customization is one of the biggest factors in keeping me stuck to WoW over all the other shiny MMOs that pop up. Something about being able to change anything that ever slightly annoys me is just satisfying. Don't like where the map is? No problem. Unhappy with how buffs are displayed? It can be fixed. Bejeweled addict? There's an add-on for that too.
I've been spending much of my time lately in beta, and in order to test things, addons are disabled. How can a healer survive in a world with naught but the stock ui? I know, I'm being over dramatic. There's a handful of individuals that prefer the stock ui, but for the majority of us, it simply isn't an option. But, when left with no other choice, there are a few things we can do to get by.