I also like Visitherms, but Ebo's are probably your best bet. I have heard they went out of business or something but another company will be taking over production of the heater we know and love.
If you can get a submersible heater they are really more versatile in terms of optimal placement in the tank. I have some non-submersible Ebo's so check the label carefully and be sure it actually is submersible.