http://www.newegg.com/Product/ProductList.aspx?Descript... I think the Star tech and Silverstone are the best.
You need to add dust filters to your intake fans, it's also better to have a little more intake CFM than exhaust this keeps it from sucking air in from vent holes or corners and seams.
This will usually mean you will need to remove the fan and filter to clean it as needed.
I just use a can of compressed air to blow the dust out of my PC when needed not remove every part, just be sure to hold the fan blades still before doing them so the fan can't spin so fast it burns your bearings/ sleeve.