All clustered keys must appear in all nonclustered indexes. If you don't explicitly specify them, SQL will add them automatically.
I explicitly specify them when the index function requires them, otherwise not. That way, if the clustered index changes, the index definitions don't have to.
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".