On the DevDays 2006 I saw a session where Scott Guthrie was talking about Atlas (former codename for ASP.NET Ajax). I was intrigued by his way of enthiousiasm about new technologies. Since then I visit his blog once in a while, better: RSS keeps an eye on him :-).
He has a nice section about ASP.NET 2.0 Tips & Tricks that I would like to recommend.
Also a nice site to remember is the ASP.NET Videos page.