Wow, again this is a tough one! If I had to choose, I would say the Sun bear (Helarctos malayanus), which is what I voted for in the poll. The reason being their unique and unusual morphology and small size (55–143 pounds). I find it quite fascinating that there is a bear species in which the adults weigh less than I do (I probably like food a little too much... but all jokes aside, I would be very underweight if I weighed as much as a Sun bear at my height). The black coloration and yellow crescent-shaped marking on their chest is a beautiful color scheme. The size of their claws in proportion to their feet is quite intriguing as well. On my first visit to the Lincoln Park Zoo in Chicago in 2003, I had nostalgic memories viewing their sun bears, and though there exhibit may have been narrow, it was still adequate in my opinion and I miss them. My mother being from Chicago, showed me around her hometown which included her childhood zoo. My first experience with Sun bears however was in Sun Bear Forest at the San Diego Zoo during my childhood visits. Pardon my digression, but I was born in San Diego but raised in the Greater Los Angeles Area and the Inland Empire/Riverside and San Bernardino Counties (Mostly there). I live in Tucson now, and I am sad that the last Sun bear at Reid Park Zoo died just before I moved here.
For my favorite bear species, my second choice would the Spectacled/Andean bear (Tremarctos ornatus) and the main reason being, with my keen interest in Cenozoic mammal paleontology they are the only living/extant members of the members of the subfamily Tremarctinae, which Short-faced bears (Arctodus sp.) were also a part of. Being South America's only extant bear species, not just from a taxonomic standpoint, but also a geographic one, they are by definition what you could call living fossils. Their position in that lineage is easily noticeable looking at their morphology. It is just absolutely amazing when I see Spectacled bears in walking around in flesh and blood, realizing that all of their closest relatives are only to be seen in the fossil record, what a surreal experience! I am glad to have them at my local Reid Park Zoo.
My third choice would have to be Sloth bears because of their restricted distribution range to the Indian sub-continent, their mostly insectivorous diet, and though Asiatic black bears (Ursus thibetanus) also have this, the manes around their necks.
Pardon yet another digression, but being that I prefer the phylogenetic species concept to the biological species concept, I personally think that several ssp. of Ursus arctos should be split off as separate species, most notably the Apennine brown bear (Ursus arctos marsicanus), Tibetan blue bear (Ursus arctos pruinosus), and the Gobi brown bear (Ursus arctos gobiensis). Many authorities consider Ursus arctos marsicanus to be synonymous with the nominate European brown bear (Ursus arctos arctos). Being how long the two populations have been separated, I strongly disagree with that! Especially being that ssp. marsicanus and ssp. gobiensis are classified by the IUCN as critically endangered, designating them to full species level would enable the allocation of more resources to their conservation. I also see the PSC as more in tune with how evolution and radiation work. Anyways, the reason I bring this point up is that it would add more species to be able to vote for in this thread.