We need to build an administration portal website to support our client/server application. Since we\'re a .Net shop the obvious traditional way would be to do that in ASP.Net.
On the topic of remote andministrators, another poster stated that was an argument in favor of HTML if the admins were on a slow connection. I would argue that depending on the type of information, it may be more efficient to use Silverlight. If you have an ASP.NET datagrid populated with server side data binding, you can be downloading a ton of markup and viewstate data. Even if you're using an alrternative to DataGrid that's lighter on the ViewState, you will still have a lot of HTML to download.
In Silverlight, once you get the XAP down, which is probably going to be smaller than the corresponding HTML, the XAP is cached and so you shouldn't have that cost every time, and you'll just be retrieving the data itself.
For another example, let's say you have a bunch of dropdown lists on one of your forms which all have the same values in the list. In Silverlight, you can get these values once and bind them to all of the dorpdowns, in HTML you will have to repeat them each time.
This will get better with client side data binding in ASP.NET, which follows a very similar model to Silverlight and WPF for data binding.
Overall, I would also think that you would need to write less code for the Silverlight implementation which can increase productivity and reduce maintenace costs.