If you include Apex then check out Internet Applications here and commercial applications here
If I was starting a new PL/SQL-based web development, I'd go for Apex rather than straight from the toolkit. Consider it a Framework. Version 4 is in a preview release (available to try in a hosted environment) which may fit your timescales better than the current 3.2 release.
I don't doubt you can build capable and usable applications in any of the technologies. If your app is heavily data oriented, you may get more support from a database-based environment. If you have existing Oracle skills, that would also push towards Apex.
On the other hand, stuff like Ruby on Rails, PHP etc would have a larger number of users and more detailed control over the app. The separation of database from the application is one benefit of those technologies, which may be relevant in regards uptime/scalability.