Well, I've tried all the free ones. Didn't like any of them. Most of the ad space is too big.
But Nambu and Natsulion are great freebies.
I've bought:
Twittelator Pro
Tweetie
LaTwit
Simply Tweet
Twiltr
TwitterBox
Twittervision
Twitterific Premium
Birdfeed
After all these paid and free apps, the one that is the nicest looking, easiest to use, and fastest is Twitterific Premium. You can set this one up to have multiple clicks on a person's avatar to do different things. If you click inside the tweet, the links are highlighted for you. Replies to you, direct messages to you, and your posted tweets are all different colors so they are easy to spot.
Getting to the preferences is easy, and setting them is easy. It's not overly complicated like Twittelator Pro, which is buggy for me. The only things Twitterific Premium are lacking is a landscape keyboard and the ability to see your followers and who you are following. These are coming in a later update.
I would suggest trying out Twitterific free version for a while and see what I mean. I started out with that one, but the ad space was too big for my liking.
Now on the laptops I have, Tweetdeck is the easiest to use, even on my Macbook.
Blu, from
These guys is simply the best one for the desktop that I've used. Period. However, for some reason, the last update won't render correctly on my screen.
Just my input.