What livestock do you have in the tank and how much flow do you want/need? That'll dictate filtration. Personally, I wouldn't use anything smaller than an Eheim 2213 if you're going the canister route. But that's my preference.
As far as heat... regardless of what you choose, it's wise to use a temperature controller in conjunction with your heater to prevent problems down the road. A note on heat: Depending upon the livestock you've got, a heater may not even be necessary.