For a non-planted tank, I'd suggest using a mid-size HOB filter, and a small-mid sized canister filter. Stuff the HOB filter with sponges and/or filter floss. Clean that filter out often. Stuff the canister with as much biomedia as you can, and over the intake with a prefilter. As said by 750t, filter max prefilters will do well. I believe the filtermax 3 is the popular choice. Prefilters prevent most debri from entering your canister. Clean out this prefilter at least once a week. Depending on bioload, clean the canister once every few months. What I would use is an Aquaclear 300, and a Filstar xP 2/3.
For a planted tank, two small-mid sized canisters will do fine. Once again, cover the intakes with pre-filters, and stuff those things with as much biomedia as possible. Clean out those prefilters at least once a week, and the canisters once every few months. I would probably go with 2 Filstar xP 2s.
Just a reminder though, there's generally no such thing as too much filtration. As long as your fish can handle the current produced by the filters, more filters is generally a good thing. All of my tanks have multiple filters on them. Each filter acts like a failsafe for the other filters in the tank. If one should fail, the other filters can pick up the slack until I can replace/fix the failed filter. I can also clean out my filters on a rotating timetable, which will minimize any small chance that I might accidently kill off too much bacteria (this is unlikely to happen though). My 66 gallon malawi tank has 4 occupants in it... but it has enough filtration to run a decently stocked tank of nearly two times its size (2 AC300s, 1 Fluval 404). My planted tank has one Eheim 2026, and one Fluval 404 on it. I would have more, but my angels probably wouldn't like it too much.
HTH
-Richer