I am looking for a good asp.net froum (paying for it is OK) that (preferably) has an integrated chat mode, unicode support, language pack support, with heavy CSS support a good bonus.
Yep. Performance is claimed to be brilliant e.g. http://blogs.msdn.com/ is powered by CS and just two servers.
Its a lot harder to mod than Snitz, you really need to know what you're doing in C#. It has a lot of bells and whistles which a lot of people won't need and sometimes its not the easiest to set up. I think its one of the best dotnet forums out there.
Just be aware that Community Server 2.0 will still be a .NET v1.1 application though it will run under .NET v2.0. It will not use .NET 2.0's security for example, nor the support for master pages. It will be v3.0 of Community Server before it is a true, native .NET v2.0 application.
Also be aware that ASPPlayground is not really a .NET application at all, though it can be integrated with a .NET site. It is still an ASP v3.0 app, as far as I can tell...