Most used Automation Frameowrk should not be the criteria to choose from. One should analyze their requirements and select the framework which suites the best. Example, if your test cases mostly check a some flows for multiple sets of data, you can use the data driven framework. If your main criteria is maximum code reusability, you can go with functional decomposition framework.
Also, what I personally think is that most commonly used automation framework should be Hybrid Framework with functional decomposition & data driven frameworks being the most common components within the hybrid framework.
As Anish mentioned you need to review your requirement and expertise in using various frameworks!!! U can refer to the web for the difference, but again these might all weigh down to your project requirements!!
I'd also like to add the the amount of available time is a big factor.
If you spend some time thinking about and designing your framework it should be possible to deliver a basic framework that works for say a data driven approach which could then be expanded to cover some of the other approaches dependent on your requirements.
I remember a post a few months ago where someone offered their framework to the forum. I thought it was a good place for people to start looking if they are interested in frameworks.