I have an existing system in postgres that I would like to move to cassandra.  The system is for building registration forms for conferences.

For example, you might want to build a registration form (or survey) that has a bunch of questions on it.  An overview of this system I whiteboarded here: http://paste2.org/JeHP1tV0

What I'm trying to figure out is how this data should be structured in a de-normalized way?

Basic queries would be:
1. Give me all surveys for an account
2. Give me all questions for a survey
3. Give me all responses for a survey
4. Give me all responses for a specific question
5. Compare responses for question "What is your favorite color" with people who answered question "What is your gender".  i.e  a crosstab of males/females and the colors they like.
6. Give me a time series of how many people responded to a question per hour

The reason I would like to get it on cassandra is because currently at peak times this is an extremely write heavy application since people are registering for a conference that launched or filling out a new survey, so everyone comes in all at once.

Also, if anyone is in the bay area and wants to discuss cassandra data modeling over some beers, let me know!