A lot of people are struggling with this because there is no Microsoft B.I. product. ProClarity has been deprecated and the Microsoft B.I. message has always been a bit muddled (partially due to the fact that the combination of Excel SSRS, etc. was not a great solution for most uses). And now we have Denali coming which makes things even more confusing.
However, what's coming is actually pretty straightforward and does bring a strong B.I. solution. It's also not that complicated, so here's my take on what will be Microsoft's B.I. solution once everything is shipping:
That's it. They've kept it pretty simple and yet provide a lot of functionality within this simple approach. The hard part is in the BISM because that is where the cubes are designed and that remains a task that requires a deep knowledge of the data schema as well as BISM itself. But like creating cubes the old way, once that is done everyone can use it. There's a good video of this from the WPC keynote, (starting at 16 minutes in).
And for those of you that like the approach of Crescent and either don't have Denali/SharePoint and/or need more control & functionality, please take a look at AutoQuery.