I'll go ahead and say it- multiple tanks, unless done correctly and you happen to live in 4,000+ square feet is ugly. It just is. Additionally, folks with multiple tank syndrome tend to collect equipment over time that may or may not be functional. It's almost always mismatched and aesthetic takes a back seat to whatever the hobbyist is growing at the time. How many photos have you seen of a 55 with a 20 long or some other aquarium under it with all of the cords, mismatched lights, etc? It's just not attractive, and I actually like this stuff. Finally, multiple tanks tend to get away from the user, so instead of one moderately cared-for tank, you wind up with six poorly tended aquariums. On the other hand, one display tank can be a huge draw and addition to a home's overall appeal.
My girlfriend of 5+ years really enjoys my aquarium, appreciates the routine maintenance, and likes the aesthetic. Actually, we both agree that a 220 would be great in the right home. She likes the idea of that more than a massive television, and so do I.
How did I form such a strong opinion, you ask? 1- 180 reef, 1-180 FW stingray tank, 1- 55 planted, 1- 75 Tanganyikan tank, 1- 40 extra tall community, 1- tub garden, 2- 10 g. quarantine tanks, 1+ desktop aquariums crammed into a 1,200 sq. ft. townhome when I was in college. My roommate was also a fish geek and we thought it would be great to have ALL THE FISH!!! Turns out, it was just ugly and everything was a mess. The place smelled. Sure, we had a lot of really cool fish, but how could you notice with all of the damn aquariums laying around?