For few months, i have been using TwitterFox (now Echofon) to update and manage my Twitter account. I don't have problem with Echofon at all in the past, until i upgraded my Firefox to 3.6 and since then i have problem with it.
Whenever i wanted to reply a tweet from my follower, i couldn't write anything after i clicked on the reply icon. I have close the Echofon window and reopen it again, tab the End key to move the cursor to the end and start writing my replies. This is very annoying for me, so i started to find several other Twitter client, until finally i saw an email from SlackBuilds mailing list about QTwitter, a new Twitter client which work on Slackware.
I download the source and also the SlackBuilds script and install it without any problem and after trying to authorize my account several times (it's not quite stable for me), i managed to make it work and now, i love it. It works like a widget, so you can just put it on your desktop and it will start grabbing updates from friends you followed.
I would recommend this application if you are looking for a Twitter client application.