Hmm...
For beauty, I would say Rapidash, Ninetales, Arcanine, Dragonair. Teh originals.
Coolness goes to Charmeleon. It isn't overweight like its successor, nor is it sickeningly cute as its predecessor--and I fell in love with it the moment it opened its reptilian mouth and burned off that dork Ash's face (in the anime).
Toughness goes to Nidoking. Somehow I find it so appealing. It gets a badass look without being sort of gentle looking such as Kanghaskan and Rhydon, or obese like Tyranitar, or deformed like Steelix and Aggron. It seems to me to be the original "saurian" pokemon (I always thought Rhydon's design copied Nidoking's too much, though it might be vice versa).
Cuteness: Vulpix. It's so fuzzy and adorable, one could imagine squeezing it and feeling its soft, warm, russet fur. I would say Skitty but it looks so...so very ET. And Meowth has no nose, which is a bit off-putting.