What filter is everyone using for your aquarium or pond?

I have an EHEIM Classic 2213 canister filter in my main tank. Three other aquariums have Hydro Sponge Filters in them.

I chose Canister filter for its efficiency, and also for its quiet nature. Canister filters are the most efficient aquarium filters because of the amount of filter media they have on the top of the high flow rate. My EHEIM makes no noise at all until I put my ear against it.

I chose hydro sponge filters for my other tanks because I mainly use the other tanks as shrimp tanks or fry tanks. All other types of filters might pose a threat to small fish fry as well as baby shrimps, because they can be sucked into them. Sponge filter does not have this problem, and it is just as efficient in biological filtration. With a single air pump and a few valve split the air tubing, I easily power the 3 sponge filters in 3 tanks.

I have details of my main tank setup as well as some videos in the sticky thread in my sig if you are interested in taking a look.

What types of filters do you have in your fish tanks? Why did you choose them?
(To vote on the poll, please pick the filter you use for your main tank in case you have more than just one aquarium).