The question as is has no answer, it should be refraised to "what are your favorite charicins" or "what are you favorite charciformes" if we want to include more of the large toothed favorites like Vamps, wolves, and ATF's which are obviously some of the most poplular fish kept by those who frequent this form.
Don't get me wrong - some of the largest teeth belong to characidae(characins) - Piranha, Pacu, Brycon, Dorado however some of the smallest shoaling fish also belong to this family including neon tetras, phantom tetras, emperor tetras to name a few brightly colored lil' guys.
There are literally hundreds maybe even thousands of differnt species classed under characidae, would be very difficult to pick a top 10 especially since most ppl have no clue that Vamps,Wolves,ATFs,False Gars, and African pike don't belong to the Characidae Family - they have their own specific families but all share a common Order. Characin is as loosley used as common fish names for example Gar Characins
are not Characidae they are of the family Ctenoluciidae, order Charciformes. From a "husbandry" or animal science point of veiw this whole forum is either labeled incorrect or used more commomly for discussion of Characiformes.