I use Rena and Fluval canisters and have been happy with them. As I understand it, the Eheim canisters are truly top of the line (I've never used one myself), but they have the price tag to match. For a tank that size, I would either run 2 large canisters, or a
sump if you can get the reef-ready version of your tank. I use Ebo Jager heaters in my tanks and I've been very satisfied with all of them. Are you planning on keeping a planted tank? If so, you'll need to decide on lighting, and with a tank that size, you'll at least need power compacts, if not
HO T5's or MH.