The apps I use for Twitter are; Twitter application, to the Google Desktop interface. This app makes posting very fast & simple & you get the top 7 feeds from the live twitter homepage.
However, Google Desktop is not available on Snow Leopard yet, so on my main home computers I use the Twitter Widget, this is on, but only allows posting, rather than having a feed as well.
The other is on my phone. You can use the web browser & Tweet that way, but is a rather laborious, so I downloaded a Twitter app from the Ovi Store & again it's very simple & has no feed, but still useful when you need to Tweet & you're away from your computer(s)
Right no more geekery...today!