MS have released an interesting white paper about how you can use some of the new SQL 2008 features with CRM - http://www.microsoft.com/downloads/details.aspx?FamilyID=b5bb47a4-5ece-4a2a-a9b5-5435264f627d&DisplayLang=en
The row compression feature, along with the sparse columns, look very useful for reducing the number of pages needed by a table, which is important for ad-hoc advanced finds which use able scans, and pre-filtered reports.
Filtered indexes can be very useful, especially on the statecode for relatively volatile entities. For instance, the ability to use filtered indexes on open cases or opportunities could make a big difference to overall index storage
I need to do some more testing before I'm convinced on the benefits of the page compression. I could see it working for large quantities of relatively static data, such as a large account or contact table, but I think the processing overhead on data modification (which is always hard to quantify) means that I'd be reluctant to use it on more volatile data (e.g. opportunities, cases, activities).