I'm using a carbon filter and have the exhaust fan blowing through that. I also have one of those little 'mountain breeze' negative ionisers in the room outside my garden. I'm not sure that has much more than a placebo effect, though. The carbon filter also has the advantage of acting as a silencer.
It seems to be working pretty well. I can't smell anything at all and my garden's just in a cupboard in the living room. Plants are fairly smelly at the mo, but they're going to get much smellier (i hope).
My gf hasn't moaned either yet and she had a good old whinge about the pong on my last grow, when I had no odour control at all. That got pretty whiffy. She was probably right, though, but I'm not going to tell her that
cheers
comfy