You may have seen this article before, but if you haven't, here's two links to an interview with Anders Hejlsberg on the design process of C# and the absence of Checked Exceptions. So far, Java is the only mainstream language that enforces the use of specifications with Checked Exceptions, and some believe there is no real use for it. Anders discusses the trouble with checked exceptions in part two.
Part 1: The C# Design Process
Part 2: The Trouble with Checked Exceptions
Another reason why not to use checked exceptions