Those are the same dimensions of a 20 gallon high tank. You are going to need more than that for this tank!
A couple of good canisters or a large canister (as in the eheim 2262, less you would need 2) would be good. You want to shoot for 4x turnover for sumps, 5x for canisters (minus eheim filters because they have a lot more media space than similarly flowing filters), and 12x for HOB filters.
My choice would be an eheim 2262 if money was not too much of an issue. If it was, 2 xp3's by rena and an Aquaclear 70. You can get a powerhead instead of the aquaclear but HOB filters are better for aeration.
If you get an aquaclear then order it from drfosterandsmith.com and change the item number from CD to CK and get any aquaclear filter (except for the 110) half off.