Fishbowl the windows-based facebook client from UXlab@Microsoft,they build it by using Facebook SDK and the Microsoft Winodows Presentation Foundation aka WPF, it's opensoruce project where's the project codeplex page, it's quit amazing application it has a wonderful UX, it has some cons but that not bad for a preview version, i hope Microsoft add more options or solve cons but in other hand it has a great pros.
Pros:
High rich user experience, i think this application is based on WPF. Fully integrated with Microsoft Windows 7 features. The ability to share Photo and can view friend's and yours. The small mini-mode feature. The vertical scrolling simulate the touch screen experience with mouse. Cons:
The group feed doesn't work, maybe work but with me not at all. Doesn't support Events, Chat, and Messages. Sometimes crash, it's not a bad thing it's a preview version. Some screen Captures
Conclusion: Fishbowl is the best and first Facebook windows client and has reach the optimal user experience with WPF technology, i can't leave it, now Facebook online just only for messages, events, groups, and activity like friend requests.
I recommend to download and try it Fishbowl, but first look at the System requirements.