I just went through eight Twitter apps for Linux to determine which will be my new Twitter client, and I thought I'd share my thoughts of them with you.

I tried four native Linux apps that I obtained through Ubuntu's Add/Remove feature under the Applications menu, and another four for Adobe Air. I decided to do this because I realized that TweetDeck was a memory hog and, though I have two gigabytes of RAM, it would slow some of my other programs from time to time. Here's my initial thoughts (I'll get a little more detailed after the tables ... and there are no screenshots).

Native Linux Apps

Adobe Air Apps

So, I'm going to list from my least favorite, to my favorite (1 = bad, 8 = good).

1. Twitter.com (Prism): This is the web interface in a fully functional mini-browser. The main reason I don't like this is if I want to use the web interface, I'll just open Firefox and if I don't want it take up the entire screen, I'll resize it. Let's be honest though, with all modern browsers having the ability to have several tabs open at once, this Prism client is kind of pointless.
2. gTwitter: I can't really say much about this one, it wouldn't connect to Twitter. I really like the screenshots and what I read about it at their website though, so I might give it a try again later.
3. Seesmic Desktop: The things I didn't like about this client were kind of nit-picky, but it's my computer and I'm allowed to be that way. First of all, this client and I didn't get off to a good start. After finishing the installation, it opened automatically, like I asked it to, then I minimized it to the taskbar, and it just wouldn't come back. I had to kill it and reopen it to get it to act somewhat normally and it guzzled memory like my first car guzzled gasoline. Other than that, you can see my comments above.
4. TweetDeck: I used to really like TweetDeck, in fact, I had it installed on all three of my computers at one point, but then I had an entire weekend where it just wouldn't accept my password, Twhirl would, so would the web interface, but TweetDeck was being a stubborn bastard, so I moved on.
5. Twhirl: This one would be my favorite client on my EeePC (which also runs Ubuntu) because of the built-in Seesmic video support and I like all the buttons, but for my desktop, where I do most of my photo and video editing, I like to have my memory available. When I upgrade my desktop (hopefully soon), this shouldn't be so much of a problem, but now, my old PC is looking for something on a RAM diet.
6. Twitux: I decided to put Twitux on my Ubuntu machine for two reasons. First, it uses less than six megabytes of memory when it's working hard. Six megabytes is something that even my grand-daddy of a desktop can handle with little to no effort. Second, it runs very smoothly in this distro of Linux, it has transparencies and it minimizes to the notification area seamlessly. There are some things I would change about it, most notably the way I have to open a seperate window (from the client) to send an update, but that is stuff I can over-look when the app uses less memory than gedit (the text editor for the gnome GUI).
   Update: After using Twitux for one night, I've decided to move it down in this list, uninstall it from my computer, and switch to Gwibber. It turns out that links are not clickable, copy/paste is even unavailable, there's no way to retweet, and messages are cut short. These are things, despite the low memory usage, that I cannot live with.
7. Spaz: Spaz, though it didn't run well on my antique Linux desktop, it runs great on my Vista work laptop. And, like I said in the comments above, I just love the sound theme.
8. Gwibber: After using Twitux for a night, and failing to get gTwitter to connect to a network, I've decided that this would be the best Twitter client for my needs. It has good themes, a limited ability to change some color schemes, and it's decently customizable, though it uses a lot of memory (compared to Twitux), it integrates all of the other features I've come to expect from a Twitter client.

Ok, so that was a longer post than I usually write up, but I'm bored, and I wanted something to do. If you would like to give any of these apps a try, just click on it's name just about anywhere it's present in this post, it'll open it up in a new window, but it will take you there. If you know of any that I missed, please let me know.