Report builder itself is for novice users (with the exception of formula's - but anyone with Excel exp can pick these up pretty quickly).
IMO, keep report builder simple for end users to get data from a well defined model.
A model can be based on a view of collection of tables. Make this easy to use so that users understand the data that is being returned!
For more complex reports that require SPs then you will need to use the report tool within Visual Studio (shipped with SQL 2005/20080. These can be difficult to novices and I would advise looking and the MS sites and/or buying a book (some good ones out there).
The building for a report with CR is not really for novices (IMO), but more for intermediate/experts.
If your going with SSRS I would advise to make various "models" for different areas of the business, so that each end user can create their own reports (my training for this only takes 1 hr) and see the data relevant to their job/role! Implementing this has cut down data requests to systems by 70%, as data wasn't easily extracted from the DB.
Report builder tutorials
Hope this is clear???