I'm curious. It seems to me that the only viable method of programming a medium to large application in Labview is using the Qued State Model Architecture. This is of course, leaving an object oriented approach aside completely. The labview programs I have been involved with have been either entirely user event driven or had a substantial portion of the program based on user events, so the QSM seems to fit well there so far.
The only alternative to QSM I have seen involved large amounts of code within an event structure and a truck load of local variables, which I can't imagine would go down