I think an african tank. I love the oddball idea, and bichirs are AWESOME!
I have one in with my mbunas, but with a tank of that size, I would do a peacock/hap tank. Lots of color, and some of them get large. Or you could do a mbuna tank and just have 100 fish in there, that would also be awesome (with a syn or two and a bichir or two for a clean-up crew, plus they are cool fish)
BTW welcome to MFK!