I'm investigating options for reporting on data in a custom salesforce application, since the built-in reporting tool is a bad joke.
The requirements are that the data needs to be accessible on-demand through the Salesforce website (likely through a web-tab, visualforce page, etc.), and must be able to do arbitrary joins of the tables, like ANY other relational database reporting tool. It is a huge plus to be able to give much of the specific report-design power to the end user, as well. Ideally it would play well with Oracle if an external DBMS is required, though this is not a strict requirement.
I hear good things about MS SQL Reporting Services, and there has been some talk around here about Crystal Reports. I'd be much obliged to get any thoughts and opinion on the various options and approaches out there.