Great advise from Bob. I had the same question two weeks ago and decided to spend a tad more and got a really superb piece of equipment from Bob Staebell over at Aristocrat Humidors.
BTW I decided to go with the system due to two other "chinese made" humidifiers died on me fairly quickly and I figure that if I have a large collection it would only make sense to invest on a quality humidifier system.
Thread is here
http://www.cigarasylum.com/vb/showthread.php?t=61566
Set and Forget humidifier system
http://www.aristocrathumidors.com/electronic.htm
Hope this helps
Edwin