Heirarchical databases and Object databases are arguably subsets of Relational databases. If you think your programming effort needs a 'higher level application model', you should go ahead and use one -- built on top of a relational database. If you have some data that you need to manage professionally, you need the structure and reinforcement that only the relational model can provide. If that means you need to pay me to build you one, then so be it.
Microsoft has a relational database on the front burner for a future version of Windows. Personally, I think they're barking up the wrong tree. If they spent more time building websites they'd know that hierarchical models with very tight scripting connections offer more performance and a higher level application model. Relational databases are good for factories and stores. Object databases map the model of the Web. Just change the slashes to dots and off you go. - scripting.com
If there's a better model than the Relational one out there, I want
If you go through the excercise of designing a relational database for your data, the nicest thing is, your data will stay that way! almost self-organizing, and it's easy to discover new uses (new ways to use your old data)!
Heirarchical databases collapse under their own inflexibility.
Object databases look pretty but tempt you into omitting some relations that you later have to back-fill using "business rules".