The number of SharePoint 2010 titles is increasing daily. If you are a SharePoint architect, developer, or designer, you need to select titles that speak to your specific needs, rather than one of the many "how to do stuff with SharePoint" titles (many of which are excellent for non-IT business leaders and users).
To this end, I created an Amazon ListMania! list for SharePoint 2010 Professionals that contains some of the books I have found to be helpful. It's not complete by any means, but I think these are worth buying.
Check out my Professional SharePoint 2010 Library list.