Bob, Tom - please see http://sqlblog.com/blogs/jonathan_kehayias/archive/2009/02/19/sql-tip-keep-your-presentation-logic-in-your-presentation-layer.aspx...
Let me be clear, my comments about the usefulness of convert are in the context of doing an import data task, or a one-off query to go to another system. For example, I occasionally pull data that feeds some SAS code for one of our statistics gurus. He asks me to convert dates to YYYYMMDD.
Now, I am absolutely sure that I waste a few cycles doing this with a CONVERT() in my query. But the system is under no CPU stress, and the alternative is to either refuse his request, requiring him to figure out how to handle native data formats on his side and go through all his code making changes... or to learn enough SAS to do it myself. That is a waste of valuable man hours to keep an insignificant load off the CPU. Those man-hours could be better spent on projects that would REALLY make a difference to performance, or to my company's revenue. In this case, common sense dictates that I sacrifice a little machine resource to save a lot of people resource.
Machines are still meant to serve man.
__________________________________________________Against stupidity the gods themselves contend in vain. -- Friedrich Schiller Stop, children, what's that sound? Everybody look what's going down. -- Stephen Stills