anything with dust filters is good.
Cooler master storm stryker/trooper has dust filters in all spots.
Most of the higher end corsair cases have filters as well...
Btw, just smoke your cig outside, its not like it takes more then 5 minutes.
Also, if your smoking more then one cig an hour that's just plain bad ( not my business, but the truth)
When i used to smoke I NEVER smoked in my house, let alone my precious computer parts.
Dust is one thing... But...
All that nasty ash and carcinogens all over a mobo/graphics card/cpu?
No thanks.