Toss up between otters (any age) and baby pandas! I used to have a horrible job that was only tolerable because they didn't block any websites, so I would always have a baby panda live cam from whatever zoo had one going in one corner of my monitor screen.
I love cat jump fails, baby elephants, baby rhinos, and all of the slow loris videos.
I watch all the goofy cat videos, but I also like to watch birds - budgies, parrots, ravens, seagulls... I love bird videos!
Dogs! All the dogs-senior dogs, puppies, and in between!
Dogs (of any age), and baby animals in general.