I bet if you did a statistical analysis of questions about SQL Server 2005, you would end up with a pattern approximating the 80/20 rule. That is, 80 percent of the questions would be on 20 percent of the topics.
I really like what Jens Süßmeyer has introduced in his blog: Screencasts aimed at addressing some common questions. The "common questions" part addresses the 80/20 rule, and the screencast format does it in a visible way that virtually anyone can reproduce and (hopefully) understand.
See http://sqlserver2005.de/SQLServer2005/MyBlog/tabid/56/EntryID/11/Default.aspx. Note the "Screencasts" link at the top of the page.