On my last seed, I built a large network of catwalks in the trees in the Swamp, mostly for hunting down Wraiths for Chains. Honestly, it looked pretty awesome to have a boardwalk up in the trees, too. Pretty much that entire biome was my base, you could say. I know people really don't consider the Swamp for base-building, but it can be really pretty when you're 10 meters up or so and can walk around like you own the place.