Haven't found any really good twitter app for maemo yet (nothing to the level of what can be found for symbian or iphone anyway). I tried Mauku briefly a few months ago but really didn't like the UI look & feel and its functionalies were far too basic.

Tried witter too but again the UI was far too rough for my taste (yes, I like pretty things that look and feel great . It also was lacking in basic functionalities when I tried it but the developer put a lot of work into it and it seems it's quite full featured now. Might give it another try.

TweeGo looks great but far too basic.

So i tend to use tweetgo.net instead. It's a web interface, so quite slow and clunky but it looks fantastic, it's very well designed with all the features you use the most just one click away and it's got the all essential functionalites (avatar, reply, old-style and new-style RT, view @ replies, DMs, auto-refresh, view profiles, view user timeline, follow and unfollow, search).