Sorry Jetster, i assumed vacuuming ones home was taken for granted! Just teasin ya ;P
But since we're on the subject, I've got a pair(one upstairs, one down)of those uber powerful, fancy, self filtering vacuums that are great for keeping the dust down in our 100yo home. I still run an air purifier in my office 24/7 with excellent results. I may have to clean the filters in my rigs every 3-4 months. I also keep the door closed and forbid any of our hairy family members access unless I'm in there with them.
Positive, negative...like most pc related debates, i honestly dont care enough one way or the other what people choose to do with their rigs to keep them cool and dust free. It just isn't a big deal no matter how you slice it. If your way works for you...
JUST
DO
YOU
My contribution to the debate? I generally go positive with high static pressure inlets and high cfm out but it depends on the case im using for the specific build. The exception is my main water-cooled rig. I run high static pressure fans on all my rads and the rear exhaust with varied curves for each.
I usually follow the age old mantra of bottom, front and side inlets, top and back outlets but again it depends. Being that there are so many different cases and configurations, not to mention client requests. One rig may be positive while the next may not.