A big new feature in Neo4j 2.0 are node labels and real, automatic indexes. Here you can quickly get an update on this extension of the property graph model.
You can watch the presentation here.
With the new node-label feature you can assign any number of types from your domain to a node. Imagine labels like Person, Location, Product, Project, User etc. Adding, querying and removing labels is supported in all Neo4j-APIs: Cypher, Java-API and REST-API (Batch-Inserter is in the works).
Starting with Neo4j 2.0 a last missing piece to Cypher functionality was added too. The new labels allow to provide label-based indexes which are handled automatically by the database. That means after an index is created all existing nodes with the label and properties are added to it behind the scenes and after the completion of that task the index will be updated transactionally.
These indexes are used by Cypher to perform index based lookups based on the label and properties that are part of the index. That either happens automatically for simple expressions or with an explicit index hint.