I totally agree about blindly accepting missing index recommendations! 🙂

We run a process weekly that checks the server uptime (3 days or greater is our criteria), then capture all of the missing index recommendations across all of our databases/customer queries. I review them, then determine if any might make sense to implement.

Ami Levin (http://www.sql-server-performance.com/2010/logical-reads/ ) had a good article that discussed the missing index recommendations and doing further fine tuning.