In this blog post, Erika Ehrli announced start of a series of posts that will guide you through the most interesting 2010 features and resources available for developers.
Now starts by introducing the top places/content which recommends if you want to learn more about Office 2010 and SharePoint 2010 development.
Jeff Dalton: Adventures In SharePoint Land : http://sharepoint.nailhead.net/2010/02/unhandled-exceptions-that-can-crash.html
His team discovered some nastiness with unhandled exceptions inside their custom SharePoint code. Specifically they found that unhandled exceptions inside of SharePoint.Publishing.LoginRunningOperationJob can result an IIS Application Pool crash.
The reason is because this class puts the delegate code onto a separate thread that when aborted can leave the Application Pool in an unstable state. Which can (and does) result in an Application Pool recycle (which is bad for very large SharePoint sites that take a few minutes to spin-up).
So you need to make sure that your delegate code is wrapped in try/catch and do NOT throw the error from inside your catch (same as unhandled exception).