It is likely that the relational model still hold out for a long period. Rather probably these never disappear completely. In any case, other types of databases are being forcefully imposed on the scene of data storage technologies. Object oriented databases, OODBMS, are very interesting and offer a valuable alternative to the use of traditional RDBMS technology with mapping layers, ORM.
In any case between NoSQL databases I find extremely interesting the ones oriented to storage of documents.
In my personal opinion one of the most interesting in the open source world is certainly MongoDB.
Soon you'll find here more details on this amazing product and related technologies.
The interesting thing about this type of database is the flexibility in defining the structure of the stored items and a native propensity in archiving of entire files within the database itself. You can think of a database such this as a happy marriage between the relational model and a file system.