Non-Free RutonyChat

Good chat for OBS.
Very good
Good program, using this chat .
Awesome chat, using it from start of development
Cool chat, all streamer could need + fast support!
This is a great all-in-one tool not only for multiplatform streamers. It will be realy usefull even if you broadcast only on twitch. You'll get chat, giveaway system, polls and alerts in one software. Don't need to start bunch of programs.
In last update was added great feature "Remote Control". Basically it allows on control some games/software from your chat with easy commands (you may saw something like that on "Twitch Plays Pokemon" channel some while ago). I can say this is a HUGE tool to make you stream more interactive.

Also, if you familiar with html/css/javascript, you may customize template as you wish. Make font to match game you play, add some effect when message appears and more.
Excellent program. Inexpensive, but functional. I recommend.