I get asked all the time about a good SharePoint reading list. I have always found the SharePoint MCM reading lists a really good start. Some of these items are blogs and papers with additional links which if the reader follows those will normally find it could take a good amount of time to traverse the entire list. There are quite a few SharePoint books out there too but these lists do not include any books. Here are the links to the SharePoint 2010 and SharePoint 2007 Pre-Reading List for the SharePoint MCM program.
So get your learn on and start reading!