Lion’s fullscreen feature is truly a blessing. While the minimalistic Twitter app Wren might look great in fullscreen, it isn’t the type of software that truly benefits from this feature. The killer mix is the 11″ MacBook Air, combined with the Safari web browser for example. All nonsense disappears, your app is everything.
Wren above shows that it looks awesome even if you have almost no functionality, and while I do think fullscreen makes more sense on smaller screens, I do occasionally use it on the 27″ screens at work as well. It just is so focused, and sometimes we need that little extra help to stick to what we’re doing.