So, I got adventurous and wanted to convert my 1.1 site to 2.0. No problem. Read up on the potential issues on MSDN and my web site didn't seem like it would have any issues. I ran the conversion and had no exceptions reported. I opened the converted project and the only issues I found were a few deprecated namespaces had changed. No problem, fixed those.
Then, I hit F5 for the first time, and I get funny messages about syntax errors in my global.asax file. OK - that is actually an optional file now, so I'll just delete it and see what happens. Next, my web pages load with a parser error. And oddly enough the ASP.NET runtime version at the bottom of my error page says 1.1. Hmm.
I haven't confirmed this yet, BUT, remember this discussion (Web Projects as Class Libs), which I loved and did. Well, I'm guessing (I'll fill you in as I discover more) that since the converter thought it was converting only a class library, that it didn't convert any of my web pages. The evidence for this is that the "codebehind" property of the "@page" declaration at the top of every .aspx page is no longer valid in 2.0. At least as far as I can tell. If you know differently, please fill me in. Anyway, that property is still in all of my .aspx pages.
So, I'm going to keep working at this one and see what I can come up with.
EDIT --
I just read this at the bottom of this How to make web projects into class libs:
"Unfortunately I'm finding that this really doesn't work well with VS2005. Debugging plain won't work. The macro above doesn't work for me. Attaching to aspnet_wp sits there and looks dumb. VS2005 does not like class library projects as web sites, I'm afraid. Unless someone has a good solution to these issues, it probably bears mention at the head of the page that these methods are not advised for VS2005 users, nor for VS2003 users who may be looking to make the jump with their projects later on."
...so I think what I'm going to do is convert my backed up 1.1 app BACK into a web app, then re-convert it into 2005 and see what that does.