I need to compare the end of strings against a list of possible ending in a stored procedure. It will be called a lot and there are around 10-15 candidate endings. At this point
Parsing strings will have an overhead, best suggestion is the LIKE '%foo' OR as an option. Certain indexes will take advanage and do Seeks over Scans.
You'd have to benchmark to see if suitable but would be easily testable.
Check this out regarding LIKE and INDEX http://myitforum.com/cs2/blogs/jnelson/archive/2007/11/16/108354.aspx