I've been looking at a couple of book around architecture for .net:
Microsoft® .NET: Architecting Applications for the Enterprise - Dino Esposito
ASP.Net 3.5 Application Architecture and Design - Vivek Thakur
Are these worthwhile, or are better resources to be found on-line? Does the patterns & practices Application Architecture Guide 2.0 pretty much cover it?
Heres a good one.
Patterns of Enterprise Application Architecture
I would suggest my book ASP.NET 3.5 Social Networking if you are interested in learning how to build a social networking site from the ground up in an enterprise manner. It utilizes MVP, DDD, Repository, etc.
Outside of that Dino Esposito's books are always good. I also always suggest any C# design patterns book that you might locate. Take a look at Applying Domain-Driven Design and Patterns: With Examples in C# and .NET by Jimmy Nilson too.
Microsoft ASP.NET and AJAX: Architecting Web Applications
Beginnings of a Flexible .NET Architecture: A Simplified Config Service by Satya Komatineni
NET Patterns: Architecture Design and Process - by Christian Thilmany
NET Web Services: Architecture and Implementation - by Keith Ballinger
NET Framework Essentials - by Thuan L Thai, Hoang Q Lam
.NET e-business architecture By Robert Amar, Matthew Baute, Don Benage, G. A. Sullivan
.NET architecture and programming using Visual C++ By Peter Thorsteinson, Robert J. Oberg
I think those books are mainly published before Asp.Net mvc comes out, so it is mainly focus on Asp.Net WebFrom work.
If you start a new project and use more agile approach, then I would recommend reading some asp.net mvc book.
Pro ASP.NET MVC Framework is a good book.
I'm surprised no one has posted
Framework Design Guidelines: Conventions, Idioms, and Patterns for Reusable .NET Libraries (2nd Edition) (Microsoft .NET Development Series) by Krzysztof Cwalina and Brad Abrams.
I read the first edition and it was great. It's not entirely ASP.Net specific but we based our enterprise web apps off of many of the principles in there.