Ooh, my head hurts. Too many options, but this article is a good place to see the variety post-relational databases. It's also good to see that innovation is alive an well in the database arena. I think that it is also good that all the options will make a good architect think about his design. To use these highly distributed designs you give up things, like umpteen indexes per table, ACID compliance, a column for every day of the year, and 20-way joins.

I think its a good to go away from relational and look at these things and come back and look at your current practices. Maybe every attribute doesn't need a column and an index. Maybe use a JSON bag to hold the loose parts. Maybe throw away a bunch of indexes; create them on the fly for the monthly report. Maybe you can give away some of your referential integrity.