I personally don't really have any data on my phone that isn't already backed up for free, but my usage may not be typical.
All my contacts are stored with Google and all my images get uploaded to Google+ soon after I take them. All the other data on my phone are for apps that work off of web services (Google Docs, Facebook, Twitter, etc) so I don't have to worry about losing any of that information. Google even remembers what apps I have downloaded or paid for so there is no reason to need to secure those.
The one thing that I think data protection plans could be good for is wiping the data, but if you have an excellent password on your phone then you can be fairly sure your phone is secure. Just in case, I have Lookout Mobile security installed on my phone. It has a 7 day trial for its security features, which includes a data wipe, that you can activate on your phone after you have lost it/had it stolen to wipe the data. You just need to be sure to turn on the setting in Lookout's options before it gets lost for it to really work.