[Raff]

Thanks for the tip!

However, iCal is a really bad tasks management application, and its today view is neither able to just list today tasks, nor to display it selectively as OmniFocus (I would have to deselect all calendars but one).

As OmniFocus is intented to be a task manager focussed in focus, it seems logical to ask for a straightforward "today" focus.
So that I would be able to focus on my daily tasks, and only that. Seeing the whole bunch of tasks is great for organising; seeing the today tasks is great to process first what we have to have processed today without a fault.
I don't see the point about pure GTD, because if such a view exists, you are not forced to use it, and if it may increase the productivity of some of us, helping us to "FOCUS" on our today task, I think it may have to do with this great piece of software. Don't you think so? :)