New features in CRM 2011 as part of Update Rollup 5

Dialog Enhancements

Earlier

Now

Added Support for Date and Lookup fields.

Earlier

Now

Support for contextual URL.

Charts

Earlier

Now

Adding Series and Category.

Send email activity

Earlier

Now

Option for Inserting Hyperlink

Auditing

Earlier

Now

Audit User Access

http://msdn.microsoft.com/en-us/library/hh547392.aspx

Improvements in Duplicate Detections

Get the complete detail here

http://blogs.msdn.com/b/crminthefield/archive/2011/10/26/podcast-and-overview-microsoft-dynamics-crm-2011-update-rollup-5.aspx

Hope this helps.