Friend Me for Facebook
This facebook app is built for the tablet OS and works well. The interface is clean and simple
Plume for Twitter
This app is a highly customizable twitter client with a newly release Honeycomb / Tablet interface.
Stay on top of trending Twitter feeds with this app!
This Google+ app is full of win. Keep on top of all your circles and access the features of Google+ (some only available to Android users!).
FriendCaster Tab for Facebook
Facebook app for your Tablet device. Also has a really neat widget!