This is a very good point.. I make no bones about it - I never go for 'silent' builds - I go for QUIET builds. I think actually a nice quiet 'woosh' type of noise is pretty pleasing. If you greatly restrict the intake you end up with the CPU or GPU fan really cranking up to compensate (if you are running a high powered build). And this is very annoying. I'd rather have several fans spinning at comfortable levels then one or two fans spinning like crazy.2) If higher airflow is needed, then the more open vents probably work better. There's something really annoying about the effect of air resonance in a mostly closed case with higher speed fans (or higher level of component noise); the noise becomes tonal. Personally I prefer the case to be completely open if the fans/noise is higher, this tends to keep the noise more broadband. Enclosing this noise just causes too much "booooom" effect.
Also the woosh type of noise will cover up HD seeks to some extent - and that is a pretty annoying noise as well - best to use a SSD if you can for this reason..
So the question is how much wattage is your build going to pull. Someone doing a Zacate build will likely be okay not moving much air.. OTOH I run a 6950.. So I really like to have my intakes blowing right to that video card..so it doesn't have to spin up much.
I don't agree with the OP theory on filters at all though. They are very beneficial. If you use both positive pressure and easy to clean fan filters you are going to have a very nice and neat case. The FT02 tested out to be one of the QUIETEST cases and one of the BEST COOLING cases on the market - and it uses this theory. But you can do that with many regular cases too.. I mean who really needs optical drives nowadays... one external one is fine for me. I barely use em.