Eunice is mine. I actually don't have much experience with sheep, but Eunice seems pretty cool. Only sheep I've actually had though is Pietro, and he gave me nightmares. I'm sorry if he's your favorite, but I can't have him in my town because he creeps me out way too much.
Sheeps are very fluffy and cute. I'd picked the most adorable ones out there(also a black sheep in the bunch...literally) which are Muffy, Etoile, Stella, and Wendy.
I love Willow. I know a lot of people dislike her because of her bright color, but I think she's sassy and amusing and cute and she always gave me lots of gifts.
Nostalgia-wise I'd say Baabara and Vesta as I lived with them in Wild World. They were so sweet.
I like Willow and ?toile quite a lot too, they're very colourful and cute to me