Best chat app?

Hello,
I am looking for a chat application to implement it to my website. I don't have idea which to use or which is best. I came across RumbleTalk and Cbox but still looking for more options before I decide which to take.

Have in mind I want to be able to post youtube videos and charts into it and I also want to have option for design makeover.

Thanks!!

Eddies21 it's wordpress site or ?

Well I started researching on my own then. I made a lot of research in
finding a chatroom for my website. I used envolve for a
while till they closed up, pitty. I tried IRC but I truly did not like
the look and feel and the "mess" of text in there.
I had several points which are important to me.
1
– First I needed a chat that can be seen in mobile (all versions) so I
narrowed down the search for html5 chat room that look good on both
mobile and pc.
2 – I needed a custom design, I needed my background to be black or transparent. This was very hard to find (my site is dark).
3 – I do not like to install the chat in my server as this is high cpu and resource consumer. So I need a chat service.
4 – Lastly, I needed the ability to add youtube videos and upload files (technical analysis).
I have checked several chats and only 2 met my needs, RumbleTalk and Cbox.
I choose RumbleTalk finally as it can be integrated into my page and not only as toolbar.

http://s2.postimg.org/4y74zwneh/2012_06_13_1109.png