Yes, basement is the safest place to locate big tanks, but what's the point of having a big show tank in the basement where no one, but you can appreciate. A show tank is a piece of furniture or live art that ought to be visible in the living area where visitors can appreciate.
Canister is no safer than a sump system because it has O rings, clamped parts, and external plumbing that can fail from wear and tear or human error. HOBs are the safest because there are no external plumbing to leak. Even an air driven sponge filter has a slight chance of leak if the air hose fells off.
I have a 125 gal show tank in my living room which I lined up three Penquen 350 HOBs in the back. I only trust HOBs and no other filters as any flooding disaster can cause $$$ of repair cost in my hardwood floor. They do an exellent job in keeping the water crystal clear despite having to change all filter pads twice a week, but it's easy and worth it.
Well, we spend most of our time in the basement actually. The basement is a finished walkout basement, no rooms but the entertainment center is there and oh yes....a mini bar.
