[Haskell-cafe] Easiest to use NoSQL storage with Haskell?

Hi, What Haskell package to work with NoSQL storage is both mature and easiest to use? I need persistent storage for simple key/value lists (not complex JSON docs). CouchDB and Cassandra seems to be overkill for my needs. What about Riak, MongoDB, Voldemort, etc. ? Thanks! Dmitri.