I operate in Web environment where all READ ONLY functional content is served up out of a SQL Server database and then rendered on the site. All "GET" stored procedures have the SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED statement in them. This has the same effect of putting a (NOLOCK) hint on every table in the SP. If you are using Dynamic SQL from the application layer, JAVA or .Net, the isolation level can be altered at the connection level.

We have found this to be a huge performance benefit and have also seen some unexpected benefits. It makes mass data modifications and content deployments to the site doable while we are up without ill effects on the performance of the site. This ofcourse has the same dangers as mentioned above. The read uncommitted isolation level can result in a dirty read.