As my role in Maximizing ASP.NET winds down leading to release, I have to say that working with the folks at Addison-Wesley has been a really good experience. They bend over backward to give you the support you need. I felt even before this that they had the best ASP.NET titles on the shelf, and I'm really excited that it was them that picked up the project.
On a side note, I noticed at Border's last week that there aren't really as many ASP.NET books on the shelf as there used to be (casual observation, not a scientific statement). Before Wrox went down the tubes and was sold, there were a lot of really quality niche books that covered specific areas (threading, text manipulation, performance, etc.), and I don't think those areas are being served now. Granted, with such a narrow focus, I don't know what the market is for those books. Did they even sell three or four thousand copies? I get the impression that it's hard to justify publication of anything that doesn't at least get into the five-digit count.