I am curious what the "best practice" is for exporting data programmaticly from SQL Server to Excel.  Is it best to do it straight from SQL Server, or should I do it with in my C# code?  My program is going to pull the data, put in the excel file, then email the file.  So I could write an SP that gets the data and puts it in the file, then have the C# code run the SP and email the file; Or I could have the code do everything, pull the data, export it & email it.

If it is considered better to have the SP do it, why and what is the best way? ROWSET functions?

My first thought would be to use SSIS.  But, there is nothing wrong with doing it using C# code as well.  One thing that I try to do religiously is to access the database only through stored procedures.  So my recommendation would be to write a stored proc to retrieve the data and then use C# to do the rest of the job (i.e., storing the data to a file, and e-mailing it) if you are more comfortable with C#/.Net than SSIS.