The big advantages of cannister filters are their efficiency, ultra quiet operation, and media capacity. Also, the bulk of the filtratioon unit can be hidden out of sight. Their disadvantages are cost, initial setup, and opening them to replace media. Fortunately, cannister filters require far less maintenance than other filter type - I've only opened up my Eheim 2026 three or four times in the two years I've had it. If you can spare the cash, I would recommend a cannister over a HOB
any day, but Aquaclear and Penguin make some fantastic HOBs that would suit your needs nicely.
A Fluval 104 or 204 cannister should provide lots of filtration for your tank.
I'm not sure what you mean by hooking up multiple tanks. If you mean sharing one humongous filter between several tanks connected in series, I would advise against it because if one tank gets a disease, all would get it, and if the filter fails, all your tanks crash with it.
If you mean hooking up a smaller secondary tank to a larger show tank, check the DIY
forum for sumps. People use heavily planted sumps to add biological filtration to their setups, and as a way to hide ugly equipment like heaters.
A terrarium containing aquatic and terrestrial plants would look really nice and serve as a sump at the same time. I have no first-hand experiences with sumps or terrariums, so hopefully others will chime in.