I want to develop a 3d environment to be used for meetings and other such functions.

Each attendee could log in with a customized avatar and could collaborate and discuss via voice and text chat. I would like to add in multimedia content features as well into the environment.

I need help regarding platform selection preferably I want to implement it as a web application with no local installation. I'd like to avoid a browser plug-in unless absolutely necessary.

I don't know graphics programming so I'd prefer an approach that uses existing platforms and off the shelf software.

I have considered the following options thus far:

* WebGL
* Google O3d
* web 3d's X3D
* VRML
* X3doom
* Sirikata Platform
* yogurt3d
* Unity3d
* Jibe
* OpenSim
* Papervision3d
* Flash
* 3dmlw
* Java3d
* Infinity3d
* Cube3
* CloudMach

Are there other possibilities?