What is 'close' to asp.net for development
 

I do some development in apt.net using C# via Visual Studio and ado.net.
The integration of Visual Studio with the language and the database
connectivity objects... and ESPECIALLY the easy drag/drop screen widgets
(which creates the code to use them) is very nice. It makes developing
web-based applications easier (but maybe not better... not the issue
rightnow.) At risk of getting flamed, MS did a good job on ASP.NET from
the developer's point of view.

On Linux I usually code dynamic web apps via a plain old text editor
(mostly in PHP) and use the ADODB database abstraction layer to connect
to MySQL. It means I have to code (or generate) a lot of html and
javascript for screen widget 'events' etc., and it's cumbersome to
separate the presentation code from the business logic as is done so
well by Visual Studio.

What is 'close' to the ASP.net in the Linux world that is MATURE (as
opposed to the Mono Project which is still a work in progress)? It does
not have to be free. Cost is no object.

Is it IBM's websphere? Something from Oracle? Maybe Eclipse with JSP?
If a mid-size or large organization wanted to standardize on Linux and
have something VERY MUCH like the ASP.Net development platform;
something that would give them the ease of development for the
programmers, what should they be looking at and from whom?

Thanks,

Al