For all the noise they make about being Mac people, Microsoft's MBU don't seem able to turn out anything decent. The latest version of MSN Messenger, shown in this MacWorld news item continues to appall rather than appeal.
Part of it's Apple's fault. There's no set of standard icons that developers are encouraged to use, so although it would make sense to use either the Mail.app icon or Mail's "Compose" icon for Messenger's "Mail" button, they probably didn't feel in a position to do so. Which means they got Microsoft artists to draw the icons and, unsurprisingly, they end up with a bunch of icons that somehow manage to look out of place with their Microsoft house style. (I'm not an artist, so I can't really explain what I mean, but there's a very unsubtle use of color in Microsoft icons. They're less uniform in shape than Apple's ones, which tend to leave the impression of a full square. And Microsoft icons have a habit of using a different set of analogies to the familiar Apple ones.)
My favorite, though, is the bulbous baboon's backside of a "Send" button. The oversize "Send" button looks odd enough in the original MS Windows version, but at least there the button's flat and drawn in a washed-out color, and so manages to remain relatively inoffensive. (What's the send button for, anyway? Who broke their return key?)
Interesting that they use a drawer, just as Apple have removed the one from Mail (judging by MWSF2005). Drawers sounded like an interesting idea at first, but I can't think of an application where they've really worked out. Everything I use falls into one of two classes: the always-open class, like Mail and Preview, where you need the drawer's contents to use the program, and all the rest, where you never open the drawer and don't even necessarily remember that there is one.
I'll stick with AdiumX. It manages to look perfectly at home.