It looks like we are getting even closer to an Apex 5.1 release as apex.oracle.com just got upgraded to 5.1. Application Express 5.1 has a number of really nice features in it.
A simplified form wizard, new Theming and the Interactive Grid are some of the new 5.1 features. We are all really looking forward to the release of Apex 5.1.
You can test these features out at https://apex.oracle.com/ where you can get a free account to play with.