I'm the kind of guy who likes to know what's going on inside of the SQL Server engine, even if I don't have to apply this knowledge on a daily basis. One of the big benefits you get from reading a lot on the newsgroups is to hear about the "edge cases" or unusual customer scenarios that are generating anomalous behavior when the same scenario on your environment wouldn't case a problem.
Such is the case with http://www.sql-server-performance.com/at_sql_locking.asp. This article has been up for about a year and a half now, but it's still extremely valuable. Andres Taylor has put together a great article here and I have to give him credit. It's not very often that you find resources as useful as his Extended Lock Granularity Table.
Now, the next stage for me is to fully learn all of the interactions between isolation level and locking behaviors!