Nice to see the discussion on perspective. Edson, the little example image you posted is definately working better with the verticals parallel, but for many views, I find that forcing parallel verticals generates a 'top-heavy' image. Your eye 'expects' perspective. In our office we have constant battles with professional architectural photographers who (without asking) supply images to us with parellax correction as 'that is the traditional way'. My view has relaxed somewhat over the years and I have Sketchups FOV on a shortcut key and change it constantly for artistic 'punch'. I do think its important though for people to understand that in 'reality' our brain expects convergance (in ALL directions . .not just to the horizon) but that variable FOV, 2-point, axonometric, planometric and isometric projections all have their uses when appropriate.
Just by rotating an image a view degrees and tweaking the FOV can make or break an image . . .as every photographer knows. At least in Sketchup we dont have depth of field to contend with as well! Maybe soon though . . .