"Give them data and they will love you for it"
Out of the methods and tools I've used in the past, I would rank them in the following order based on abilities/versatility/usability/speed to deploy. I'm leaving cost out of it because while it is always a factor it is a different factor for everyone.
1 is Cognos (version 8)
2 is SQL Server Reporting
3 is Crystal Reports
4 is Custom written code
I haven't used any of the other tools mentioned. Cognos 8 is nothing short of awesome. While pricey, you are only limited by your imagination. It can do anything.