[Shanj]

You name it I've tried it!

$5flashchat - Integrates with vb. Your script only. Nice -has voice, design features. Not enough features for me. Some report as unstable.
123flashchat - Integrates with vb if you buy script - pricey. Also hosted. Lots of features but you quickly run into buying 'extras' and it doesn't come across as reliable. I got different quotes for feature requests all a bit messy.
Chatblazer - $20pm/ or buy script. Good. No vb integration, clunky layout, very good features. Multiple rooms, can control access by usergroup, picshare, mini whiteboard, moderated chat etc. Fairly stable. Voice is add-on and expensive.
Talkingcommunities - $40pm excellent voice, integrated browser, whiteboard. Only one room, multiple in development.
addonchat $75pa - Neat textchat with design features, good for backup.

Ive investigated and tested practically everything else around over 3 years! Around 100 different chats!

My recommend is Visichat. Newcomer on the market very keen, excellent fast actually intelligent support!!!!
Integrates with VB $95/ $200. This allows complete custom design. Alternatively hosted version from $15 -- $80pm depending on concurrent users.

Masses of features ALL INCLUDED no hidden extras! Full demo on site + admin demo.
Multiple rooms, control access per user, (per usergroups in dev. but this is for hosted w/o vb integration; if you vb integrate use vb usergroups) Guests, registered users etc options.
Voice incl. handsfree, webcam, text, avatars, transcript, picshare, fileshare, the usuals (smilies font etc) Private chats in separate windows/ private voice. Typing indicator, mic indicator, who's online indicator - members list up to 100 most recent joined on tab.
Design is compact and user friendly, very intuitive. Admin interface ditto with loads of options to toggle stuff on/off. Hardly needs documentation as it's good interface design.
I want a few more features which they are doing this month like option for mod control on who speaks, better integration for mp3, mod leading browser page.

They also do a basic 3D room, a site support messenger etc.
Also I'm talking to them about a desktop instant messenger for me.

I'm very happy with them but would like to make it clear that in recommending them highly after all my long searches I am NOT a member of www.gchats.com the company, nor do I get commission for recommending them! Just a satisfied client. I was meaning to write in about them but was busy then saw this thread.