I am using a Pacific Coast chiller and have been very happy with it. 1/6 hp motor that keeps my 60g cool at 75 degrees. A chiller is a must in AZ (I think?). For me, it definately is a must. I know they cost a preaty penny, but I had not choice and wanted a good reliable one. There are many on the market that have a fairly poor track record as far as failures. I have a friend in CA who ownes a Marine Fish store who sells a lot of them (chillers) and over the years, he has never had to return any of the Pacific Coast chillers he sells.
Peter