Well, I’ve tried a few twitter clients since I got my Acer A500 10.1” tablet, and for me, the best is Tweetcomb.
(What I really want is for Tweetdeck to release a tablet version, and I’d like that tablet version to mimic the desktop. But they’ve just been bought by twitter, so who knows what will happen there, and when?)
Tweetcomb is clearly my favourite of the available tablet apps, because it’s the most efficient for my workflow. It’s an efficiently designed workspace, and although I’d like a little more customisation, it’s pretty good as is. (Here’s an old screenshot, without the “lists” option showing top-left.)