My aquarium interests center around the characins. I am also fond of those fish which make good tankmates with the tetras: Barbs, Rasboras labyrinths, peat-spawning killifish, and dwarf cichlids like Apistogramma. In short, I like fish which are peaceful, small, and come from soft, acidic waters. (However, from time to time I pick up an unusual livebearer, particularly some Goodeids or any uncommon Halfbeak.)
I once tried some lake cichlids, but they don't "push my button." Furthermore, I hate the hard water spots on the sides of my tanks. Since I use almost all r/o water, none of my tetra tanks have these nasty white build ups.
Recently I've attended four ACA conventions in a row, even though this national convention is devoted to cichlids and focuses heavily on non-dwarfs. I've gone mostly to meet other dwarf cichlid people, to obtain new Apisto's and West Africans, and to move some of my fry. It's a great way to see people that I've come to know, but would never see again any other way. Too bad there isn't a natiional convention like this that is "all species." (But there are a couple of good regional ones.)
The aquarium hobby really is diverse -- not just in the types of fish kept, but in the full realm of keeping aquatic life. The most enjoyable time that I spend in my fishroom is [1] setting up and monitoring the breeding and rearing tanks, and [2] spending an hour or two tracking fish with my camera, trying to get that great shot.
Some guys get into the hardware of the hobby. You know what I mean. They'd rather talk about their filtration than about their fish. That is not me. Hardware is just a necessary cog. My fishroom hides the PVC and hardware, and it displays the fish.
But if there is something that distracts me from the fish, it's writing about aquarium related articles, or developing a talk or this web site.