in response to fishhead0103666@ again, I accept your apology. As for what comes to mind first regarding fish tanks, it would be a large beautiful planted tank, something like Takashi Amano's work. But I would not personally do that (and even if I wanted to, I don't have soil in my tank, just sand, and only a few plants can survive without soil). As for what I want, I want a tank suitable for keeping possibly destructive and large monster fish. So basically, a relatively sparse hardscape tank with just sand, driftwood, and rock. What fish would make me happy are show-stopping fish that people will have to double look to make sure they saw what they think they saw. So basically large oddball fish such as arowanas, gars, stingrays, large catfish, knifefish, eels, and eel-like fish, etc.
In response to Trouser Bark@ again, I don't personally own another tank suitable for large specimens. But I do have a local place or two I can take them to when they get too large for my tank, both of which have experience with taking care of the fish I want (and usually sell them).
In response to Joshuakahan@, I agree, it isn't risky short term until they outgrow the tank. I'm not getting a larger tank than the current 55-gallon I own, I totally would though if I had the space and if I was living alone. I am considering getting smaller alternatives, but the big ones that I've chosen are kind of stuck to my brain and I'm honestly hell-bent on getting the fish I want.