Beauty is the eye of the beholder. Some fish deemed beautiful by some are viewed as horrid by others (my wife hates my dimiochromis compressiceps, while they're among my favorites).
It's all down to personal preference and what you want to stock, and if your tank is compatible with what you want to stock as well as if the fish are compatible with each other.
Beauty is definitely in the eye of the beholder. I find angels completely dull and unattractive, but others love them. My personal favorites are rainbowfish, lots of color and personality, followed closely by killifish and German blue rams, but if you're doing a small tank on a small budget, fancy guppies will get you the most color for your buck, IMHO.