I personally use Corsair Graphite 230t case with total of 5 case fans (airflow as on screenshot) and if it comes to cleaning it from dust im super amazed how slow it gathers inside, even in the hot summer, thing worth noting is that I own a cat and PC itself is standing on the floor on a quite fluffy carpet (I placed a piece of cardboard under so the PSU had a place to breathe )
If it comes to temps, my I5-4690k overclocked to 4,5GHz while for eg. gaming has about 60-70C and my GPU in stress has about 70-80C with closed case