Jade- If you wanted to stick with HOB filters only, you absolutely could on a tank this size. You could run 3 Aquaclear 110s on a 170g tank. In regards to HOBs, Aquaclears are the best because of their reusable media and the fact you can use what ever bio media you want in them. Another option would be 2 AC110's and some sponge bubblers. I like to run several kinds of filtration on my tanks in case one poops out or so I can swap filters around to different tanks.
Like said, canister filters are great (I've got two) and offer a massive surface area of filtration media compared to a HOB, but they are more labor intensive in terms of maintenance. You can lift out and squeeze/rinse an AC110's media in a matter of a minute. A canister cleaning can take a half hour or more, plus you have to pray you can get it primed and pumping again with no seal leaks. You have to clean/lube the seals too if you want them to last, plus you should have spare seal and impeller kits on hand. There's always potential to getting water on the floor in this hobby, but a canister will most definitely increase the chance of this.
IMO, best option is run an aquaclear or two for the majority of your mechanical filtration and a canister for some mechanical and lots of bio filtration. This will help take the solids load off your canister and reduce the frequency of cleanings. I only have to break down my canisters every 3 months running setups like this.
In regards to heaters? They're all good provided you keep the business end out of the water at all times. Keep a "submersible" heater fully under water and water eventually gets in them. Keep the dial end dry and even the cheap ones will last years.