Dev Tools and Suggestions for RIA Project

A little Background ---

I am kicking around trying to build a controller app, which will have a bunch of hardware attached to a server, running a web server so it can be controlled remotely.

I think I am going to use ASP.NET and C #for the server side and Adobe Flex for the GUI Client Side because I saw some samples and it looks great (But I am not stuck on the flex choice - Silverlight??? )

The server side will have a database tracking states of all the Hardware attached to server.

Basic Functionality Needed ---

A) - When the user clicks a control on the webpage:
Client sends a message to server, HW state changes on server
Database gets updated on server
Client then updates GUI properties in the flex side to reflect new status.

B) - If something happens to the server side forcing HW status changes:
Server Sends message to Client (Or client Must Poll Server??)
Database gets updated on server
Client updates GUI properties in the flex side to reflect new status

C) – Hardware can be added / configured, including graphical representations of the hardware in the GUI.

D) – At some point, Id like to be able to add streaming media -

Now Some Question ---

1 - I would like the server side to continually update the web page that will be served to the client side so that any time a client access the web server, the GUI reflects the current state. I do not want the user to connect, load all the controls in the client side, and then poll every device on the server side to synchronize the states of all the items on the client GUI to the hardware on the server (this would take forever). Is it possible to avoid this with current web technologies?

2 – I considered ASP.Net C# and Flex without really understanding all their capability. Are there more suitable tools for this type of application? (Limitations being I want the page to look nice graphically, and I don’t want end user to have to install a run-time engine, yes I know Flex will need flash player but it’s pretty common.)

3 – My original Idea was to build this App completely as a web page, and have the local client (running from the server machine) access the GUI as localhost IP. Thought being, Then the local and remote clients would see the exact same thing. Am I reaching here? Is this impractical?

This question is broad, due to my lack of understanding about how all this dynamic web page technology works. I have been a programmer for years, but mostly stand alone console apps.


Any useful info people can suggest on choice of tool, or general architecture would be welcomed.

Thanks
Mike