I love Oracle. A production database is like a bakery, giving out the sweet smell of freshly inserted records, with data nicely baking browned through frequent updates. The price of Oracle is surprisingly reasonable nowadays - yes it is more expensive than bread, but the low end version is cheaper than Microsoft SQL Server, and it provides heaps more functionality than MySQL. We used to use some PostgreSQL, but the latest pricing structure makes it cost-effective to use Oracle for most of our systems.
In celebration of Oracle, I've written an advanced tutorial on using ADOdb with Oracle. ADOdb is a popular PHP class library for connecting to databases that I designed. The article covers BLOBs, REF CURSORs, and complicated stuff like binding.
I suspect that some open source advocates will be puzzled by my praising Oracle. Well my work involves pushing around massive amounts of data around. The cost of using a commercial database is only a fraction of the total software cost. People say that open source software has great technical support - yes it is good, but what our business needs more is marketing help, which Oracle provides. Using Oracle makes our products more attractive, as customers like to feel that they are running large and powerful applications on their systems (and it's true, we aren't kidding them). MySQL and PostgreSQL don't feel sexy to our clients. Selling based on price alone is great for commodities, but it is probably the worst way of selling customised software.
It's true that Oracle is complex, but there is a reason why it works the way it does. Oracle is designed for scalability and extensibility in a high data throughput environment. If you don't develop or maintain systems generating gigabytes of transaction processing data a day, you don't know how hard it is.
The other thing I like about Oracle is that it has a fantastic developer community. You have Oracle staff like Tom Kyte who will answer any (reasonable) Oracle question you have for free, and Chris Jones who is quietly working away at making PHP work better with Oracle.
PS: Eric Sink has a great article on software pricing.