In trying to maximize my productivitah and agilitah, I've been forcing myself to write absolutely as little code as possible, and to lean heavily on framework pieces that let me get it running now, and refine/refactor/redo later:
1. ASP.net 2.0 -- the built in support for users, roles, master pages, data binding to arbitrary objects, integrating SOAP web services, and mobile web pages is both well documented and fantastic. Been around for a few years, hardly news. Well understood and can scale like a mofo if I'm ever so lucky.
2. ASP.net AJAX and the AJAX Control Toolkit -- these are newer and totally rock out. In my book, there are only two long-term high-productivity high-sustainability conceptual approaches to AJAX. One is the ASP.net AJAX approach (there are also libraries on other platforms that use this same method), where simple declarative markup causes automatic generation of relevant client side code, server side endpoints, object marshalling, etc.
This allows really neat tricks like the following: start with an asp:calendar tag for a calendar control. Bind any sort of logic you want to its ASP.net post-back driven events on the server -- as simple as changing the UI or as sophisticated as booking a reservation on the selected date. Now just wrap the tag inside an asp:updatepanel like this
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Calendar ID="Calendar1" runat="server"/>
</ContentTemplate>
</asp:UpdatePanel>
...and now your post-back is done, server code run, and results rendered all in an AJAX call.
The other sane approach is the Google Web Toolkit / Script# approach, of writing the client app in Java or C# with static typing, interactive debugging, refactoring, etc., and then compiling to Javascript as a build step. Of course I did succumb to one use of the "unsustainable" approach -- hand-coding a particular AJAX feature I wanted -- but I think that most typical AJAX cases can be handled by one of the above structured approaches.
3. SubSonic, an ActiveRecord implementation for .net -- I'm a big fan of object-oriented design, which usually means a heavier OR/M layer to a substantially distinct RDB schema. But for a simple project with a tiny straightforward domain model, I wrote the schema and went with ActiveRecord instead. I am extremely impressed with SubSonic. It does just what you want, code is easy to debug in the rare case something blows up, and poof! automagic simple data-accesss layer with beautiful generated classes, and no code.
Using these three framework pieces, I've managed to put together a site with users, roles, profiles, a dozen pages, a half-dozen mobile pages with automatic device-specific rendering, data access for the actual domain objects, mashing up a couple of external services, AJAX where appropriate ... in probably less than 250 lines of hand coded C#, and less than one man-week of effort.
Time (and some free analytics data) will tell whether it's useful to anyone besides myself, and whether I should expand it with more sophisticated functionality. But of course the beautiful thing (and yet another web 2.0 cliche) is that with this little effort to build, and a few bucks a month to host ... it's a fun time and who cares if no one else wants to use it ?