Some search I did recently for help on a SQL Server topic led me to http://www.brentozar.com, which I have found to be an extremely useful site. Although I've worked with SQL Server for a number of years, I am much more proficient (and comfortable) with Oracle. (Now that I'm older and wiser, I won't get into which is better... there's room for all RDBMSes in this world.) But one of the things I like most about the Brent Ozar site is how high-level it is: they delve deeper into issues and provide a lot of good evidence for their assertions. It's also nice that they share their knowledge (and scripts) for free. And they have a good sense of humor.