As I've written about a hundred times now. I'm currently rebuilding this site - don't stop reading, I really am this time!
So, I'm in the process of defining an architecture - rebuilding the site is more about my playing with some new technologies rather than actually making a site thats' for anything. The architecture I choose will have many of the features I'd expect to see in ASP.NET 2.0 - with a view to converting once I get the bits.
The way it is currently going is to use a version of MasterPages , maybe taking a few pointers from Paul Wilsons articles on the subject. In addition I want to have some sort of MVC type implementation, where I can control the flow and navigational logic from a central location - there's an approach I've used before in Java where the Controller is responsible for filling the page Context with the information which the page needs to render, the page then just has to access Context to populate itself, might see if this is easy in ASP.NET.
Of course, I'm going to be heavily using the MS Application Blocks  - I can't emphasise enough how fantastic these things are when building applications!
One thing I really dislike about the current BlogX - the blogging engine currently powering this site - is that it doesn't use SQL Server- this essentially means my information is stored on the server in plain XML - it's hard to index (no search!), if some other format comes along, it'll mean writing a hideous XSLT to do the transform and I can't load balance the site (OK, not a problem any time soon, but the Architect in me objects). Plan will be to replace BlogX with another engine (with a better architecture), this will be based on SQL Server, have built in support for encryption and compression -I hate the fact that right now, big old chunks of unencrypted XML contain the config settings for my site and regularly fly through the ether - this is NOT secure in the slightest. In addition, front-end caching (even more necessary with the shift to SQL Server) - I may even have a look at caching each blog entry as an entity and then just assembling them as the page renders...hmm...