Just a regular honeywell desk fan. I don't know how I'm going to attach a carbon scrubber to it (which will probably be necessary once the girls get to flowering), but it should provide more than enough ventilation.

As far as lumens go, I'm guessing that I'll have around 4000/ft^2, which should be more than good for a CFL grow. But with color temps, would the plants grow well if I used a combination of both throughout the entire grow? Or would I need to buy a different set to use for each growth stage?