Allow for internationalization.  (Questions and answers in more than 1 language) If a language is not supported it defaults to the base text. - There will be Localization, but the feature you describe would be a big one. Too big for the first version.

You might want to consider designing it in initially but not implementing adding the multi language part.  A straight forward implementation may be to have an auxilary table for the SurveydataItem and SurveyChoice tables.  SurveyDataItemTranslated and SurveyChoiceTranslated    layout as follows:

SurveyDataItemtranslatedID

SurveyDataItemID

CultureInfo

DataNameTranslated

SurveyChoiceTranslatedID

SurveyChoiceID

CultureInfo

ValueTranslated

Then it is a pretty straight forward SQL statement to outer join each set of tables to pull the correct data when building the survey.  Even if the language hasn't been implemented yet.

Other properties for a question.  (SurveyDataItem) (Max length, validation message, validation regularl expression) - Max Length would be possible, but I think that regular expressions are too complicated for most end users.

Agreed that reg. expressions might be to complex for most but some users would be able to use it.  Could also supply some default ones for things like phone #'s , zipcodes etc..  Just because it is there doesn't mean they need to use it.

Other question types.   (Comment: Used by admin to post instructions,  Separator: Used by admin to break up / group questions, Range/Rating type:  Use a scale to answer a question(s).  ) - Too big for the first version.

Perhaps skip the range type but a comment / instruction and separator should be very similar to what you already have coded.

Soft Deletes / Inactive for questions & choices etc.  (That way data isn't lost just hidden) - The visible setting does this.

Should also have visible in the SurveyChoice talble then.

Store SurveyChoiceID in SurveyDataAnswer table. - This was not done because the choices are used by value not by ID number in the database. This will allow the ability to export and import survey's

Just would allow for better reporting but I understand why you might not want it.

Header / footer template. - I think that a header and a footer can be created by placing a HTML Module at the top and bottom of the Survey

CSS styling. (not necessarily tied to DNN styles) - It wil have this.

Copy a Question or even a survey. - It will have this using IPortable   

Not just being able to copy a whole survey with iportable but being able to copy a single question within a survey.  Makes it easier to create a new question of the same type.

Thanks for the response.

Robert