I like using the SubSonicCentral autoscaffold for playing around with my database. I realize that since I'm already in VS2008, often writing stored procedures in the database, I could just use Visual Studio's built in table data editor for this, but I like how the subsonic scaffold (and the autoscaffold) use the interface to make it easier to select Foreign Key columns, dates, etc. Also, the Visual Studio data editor has a tendency to make a "ghost' image of itself if I let a tooltip come up over any cell in the table, and then plunge my PC into a BSOD.
But one day recently, my SSC on my development PC just stopped working. I would get an error in App_Code\builder.abp (which signifies it is a Subsonic/Database issue) stating "Login failed for user ADAM-IMS\ASPNET". I tried resetting everything (IIS, SQL Express Server, Windows XP!) and still got this message, which cropped up randomly. I made sure EVERY Subsonic configuration was correct, and that the connection strings were correct. I made sure the databases (both my development one and Northwind, which SSC requires for some stuff) were set up with proper permissions for user ASPNET on my machine.
I finally solved the problem days later with a random, hopeless (in my opinion) act. I deleted my "ssc" virtual directory form IIS and remade it, then reset IIS. Ta-da! It started working perfectly again. I doubt this will help anyone else, but just in case I forget I'm posting it here.
UPDATE (8/1/2008): I figured out the problem with the Blue Screen of Death showing up when looking at tables in Visual Studio. Finally did the right google search and came up with this: http://botsikas.blogspot.com/2007/06/ssms-and-win32ksys-blue-screen.html.
Thanks to Andreas Botsikas for figuring this out!