I prefer slight positive pressure, front to back. Filters over intake fans.
My current setup has a single 120mm fan in the front pushing air over hard drives, a huge super-slow 200mm (or bigger) side fan just slowly shoving air over the whole mobo, the PSU fan exhausting at the bottom where the PSU is, and a top exhaust fan.
Overall its slight positive pressure so dust builds up only around the intake fans, but with exhaust fans at top and bottom I'm pretty sure I'm getting airflow through the whole case. Plus, the front intake fan ensures cool air goes over the hard drives while the side fan makes sure there is no hot stagnant air around video card or cpu HSF.
CPU HSF is a tower design that blows the hot air towards the top exhaust fan.
To keep it quiet, all the fans are running at the slowest speed I can select using the case's fan speed switch and bios settings. Plenty of flow directly onto components that need cool air, and the hottest air is directed in the general direction of an exhaust fan.