I had no fun in twitter till I saw first destop client. It was tweetdeck – a powerful and really nice application that had won my heart at once. However, there is a couple problems with it at the moment, and the most noticeable is memory leak. I tend to leave my laptop always on, or use hibernation. After 5-6 hours tweetdeck crashed on my Vista64 Ultimate, which I found highly annoying. Also, some users complained that it does not perform too well for users with big follower list. Thus I had switched to alert thingy, which offered Facebook support as well.
The downside of AlertThingy is lack of columns and limited Facebook support. Thus after a while I started looking for another client and found a remake of twirl – Seesmic Desktop. Since it supports both twitter and facebook (even multiple accounts) I am very happy with its performance. It is Adobe Air program, thus not OS based.
The best of Seesmic is that it is developed actively and does not crash that often. There are issues, as adobe Air is not too efficient with memory. But most of them will be fixed with time. I still like tweetdeck design more too, tho differences are not so significant.