Twitter, while being a canonical Web 2.0 poster child, has never really looked the part. After their database upgrades Sunday they've very stealthily updated their look.
The first hints that something was afoot was the mysterious disappearance of the "back" button to few your followee's previous tweets. Well that's back with a much slicker looking interface. It's a much classier look, less "done in the backroom" and more "done by an actual designer". Well done! It's a subtle change to be sure, but something that is easy on the eyes makes it easier to use.
Also, be sure to stop by my twitter page and say hi!