5 watts per gallon is the usual size, so for your tank about 350-400w. I'd use (2) 200w heaters. My perference is Jager, but lots of people here like the Visi Therms too.
Nobody really makes a very good titanium heater. Some are better than others, but they are all so problematic that I'd rather take my chance with breaking glass than a stuck on heater.