The biggest fish in the MDOP pond of course is Microsoft Softgrid, Microsoft Application Virtualization. There are also other products in MDOP that you can purchase as well. Putting together all these costs and benefits to determine your ROI on your purchased solution can be a daunting task but chances are that you will be asked to do this nonetheless. Don't worry! Justin Zarb pointed out that there actually is a pretty advanced tool that will calculate the ROI of your MDOP purchase for you.
 

Like I said, it's pretty advanced. This isn't something you'd do on your coffee break. This Microsoft MDOP Business Value Analyst was developed independently by ex-Gartner ROI experts from a ROI tool developer Alinean, Inc. This analysis tool examines current cost saving and service level improvement opportunities and management practices, then quantifies potential advantages for business value from MDOP. The tool collects information about current desktop and support operations, and then uses research by WiPro, IDC and Alinean to project potential benefits and ROI from MDOP.  

The tool does not yet take into account the recent MDOP additive Kidaro but perhaps will in the future. Try  for yourself. You just need to create an account (with a NSA grade password).