Facebook for Android
This is the official Facebook application put out by Facebook and is the one you will get if you go the Facebook website as well as the top result if you look for Facebook in the Android Market.
Upon bootup it shows a nice clean menu that easily allows you to select from your news feeds, friends, photos, inbox, profile, and notifications. The icons are large for easily selection. Everything runs fast and contains all of the options and menus you'd need to comment on others posts, search for friends and photos, and update your status easily.
A really helpful and cool feature is the little camera button right next to the status update. This will take you right to your camera on your phone; once you take a picture it will take you right to the menu to upload the photo. This is even more helpful than most features on phones that allow you to upload pics to Facebook because you can do it right out of the FB app.
One thing that is frustrating is the frequency with which it updates. You can change this if you go to the home menu of the app and hit Menu < Settings < Refresh Interval. (From that same menu area you do have some good customization of notifications). Of course like any app you have to have it up to refresh. This can be worked around by using the "Refresh" button that comes up when you hit "menu".
The widget is also somewhat frustrating. It allows you to quickly update your status but only scrolls through status updates of your friends, ignoring any filters you may have placed for friends you don't really know well. Overall, a good FB interface, not such a great widget.