A relatively new NoSQL data store on the scene is Aerospike. While we've touched on RethinkDB and Datomic, Aerospike hasn't been covered much on DZone but I thought I'd get everyone up to speed on this newer store:
[Aerospike is] planning to combine SQL, key value, and document and graph database technologies in a single database by bringing together its Citrusleaf NoSQL database with the acquired AlchemyDB NewSQL project.
-- Matthew Aslett, 451 Group
The CTO at Aerospike also had some interesting commentary at this year's Hadoop Summit 2013. They're focused on pushing the limits of SSD/Flash in-memory data processing and providing "Storm speed" (perhaps he's referring to Twitter Storm?) which is about 10 million messages a second.