I have personally found that there are a lot of economical cases that do a good job of cooling. I recommend running intake fans in the front and exhaust fans in the back and or top. I have not found a good way of entirely keeping dust out though. On my current rig, I have good filters at all intake fans, and no open fan locations, but still have some dust build up that I clean every 6 months or so. Having intake filters definitely helps though.
Something like the
Corsair Carbide Series 400R would be great. If you upgrade the exhaust fan to a 140, it would be even better.
But, if you would like to save some money, there are some more economical cases available from company's like, Cooler Master, Corsair, Antec, Fractal Design, ect. that would also do a good job for you.
Just remember to think about the way air will flow while building your case. Drive bays, cables, cards, and such will affect the way air travels through your case. Keep this in mind while planning how to pass air over your core components.