Where to start? I wouldn't discard a canister filter because of age - if it works, it's tried and true and may continue to run fine for years. Failing that, I'm a fan of the Hagen (now Fluval) Aquaclear HOB design as it affords easy maintenance with custom media. Seachem's new Tidal is a close second, although I don't like the irregular sponge. I'd go with one or two AC70's or a single AC110 for that size tank. Sponge filters are great, but typically detract from a natural look.
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As for a planted substrate, SAND. I use pool filter sand, although others report success with regular big box store play sand (e.g. sacrete). The beauty of a coarse sand is that rooted plants do well, but detritus doesn't get down under and with Malaysian Trumpet Snails, it is ... well ... maintenance free.
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Paludariums are neat, but better suited to frogs and lizards than most fish. I don't think a beta would do well in one.
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For lighting, I'd find a decent LED. I like my Finnex Planted Plus 24/7, but Beamswork (and others) have competitively priced LED lights.
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I always cringe a little when I hear a hobbyist write about "minimal maintenance" and I get attitude when I see "low/no maintenance"!!!
Not counting daily feeding and observation, a tank like that will require about an hour or so a week to maintain. This involves a partial water change (about 50%), filter and glass cleaning (and sometimes gravel vacuuming).
If a person can't find an hour a week to maintain an aquarium, they're doing something wrong or shouldn't have any pets at all!