Here are a few triggers that I use on a regular basis, so I figured I would post them to make them easier to pull down, and let everyone else give them a shot.
The first piece takes the statement or method, and puts it into the flow store on the request side:
Flow.store.stmt = DB.statement || DB.procedure; Flow.store.method = DB.method;
The response-side triggers each have a specific use case.
The DB-Statement-Timing trigger tracks the database processing time on a per-statement basis, and allows you to drill into the individual database statements.
The DB-Method-to-SQL gives a breakdown of the database methods being used, and breaks down the timing per method, with a drill down to the full SQL. For starters, it tracks the processing time for Inserts and Selects, but following the format in the trigger, it is simple to add other methods.