Usability types are often accused, with some justification, of focusing on the negative. It's easier to notice the lack of usability more often than the presence. Good usability is like a waiter that's only there when needed.
Some examples of good or improving usability:
I noticed a crew working on a curb near my work making it a more natural angle for people turning left. See the Usability of curbs posting for the original rant.
The manual for my Toyota had a complicated diagram for the situations under which you could shift to what gears (it's an automatic). I don't have to worry about it they did it right. It offers constraints that keep me from doing something stupid.
While I'm on cars, why do all those science fiction movies have cars with joysticks? The wheel is clearly the right solution.
Stephen Gass invented a saw brake. It stops the blade on power saws very rapidly if it stops cutting wood, causing only a slight cut rather than the alternative. This is what us usability types like to call constraints. It means not letting people do something they really don't want to.
I'm seeing more sites putting the cursor in the search field for you, a la Google, or the username field, because that's where you want to be. Yahoo mail, for instance, whatever else its flaws, does this right.
Between Photoshop 5 and Photoshop 6, the usability noticeably improved. Editing text on the canvas, showing selections when you change them even if they are hidden, putting the tool options in one place, these are all good things.