First off all, sorry for my bad english, im from germany.
Im "using" justin.tv for a pretty long time now and im looking on software-news-sites at least one time a day, but i NEVER saw this tool...and its epic! So why this software isn't on cnet or all the other huge software sites? I think most of the people don't know that this tool exists and watching justin.tv with firefox...so list it there and you will have like 100 times the downlaods you have now!
I have some suggestions to make. Hopefully some of the developers will read it.

- "show list" button is very good...why dont make a "show chat" button? there is enough space (yeah i know ctrl a and z, but button would be nice and is easy to make...)
- if you switch the display modes (full / frame) how to get back? once you switch du frame, i could not switch back...so maybe you can it make like the windows size options to switch (maybe F10) or something
- skins are very good! why not make it possible for user to create there on and put in on your site (like winamp)
- portable (*.zip) would be nice to have ("...put it on your stick and watch everywhere..."

- maybe the channel that was last open could be open when i start...for example games was last opened, it will be opened at the next start
- is there an option for "all languages" ?
- the last size and position is saved...very good...what would be awesome, if the window "snap in" at the desktop edge..i dont know how to explane...also like in winamp

- what about favorites channel list or bookmarks..i dont know how its called?
ok that's it for now.

I was reading some users had problems to get the stream starting (me too). i only had this red X in the upper left corner... if you are using firefox, you have to install the flash plugin for internet explorer!! get it here: http://get.adobe.com/de/flashplayer/
and you have to allow activeX-controls and scripting in the internet options!
many greetings