form platforms to integrate into CRM

I was just wondering what people thought were the best form platforms that would allow my organisation to regularly build forms to put onto our website to capture data and integrate into CRM. We currently have Click Dimensions for email marketing but each form requires a workflow to move the data to the correct location and the forms are also not dynamic (i.e. fields change depending on previous responses).

It would be nice if the forms could save a position to come back to later (like form assembly)

Allow attachments to be submitted

did some data type checks, specify which fields should be completed etc

presented different questions based on responses

easy to integrate to CRM.

integration to a payment gateway could be useful for later projects.

We currently have a click dimensions, form assembly and red form but would like to rationalise to a single form solution. 

Any thoughts welcomed!