Well....mostly true, and I'd recommend going down the SP route, although I would suggest leaving complex logic out of the database.
But bear in mind the situation where an index has a lop-sided distribution and some time it's very selective, others not. The SP will use the stored query plan which will be good for the set of parameters supplied when the query plan was created but bad in the other case. In which case the stored proc would have to be created "with recompile", which loses most of the benefit.
Not usually an issue, but always worth keeping in mind.
Mike