I generally dislike the hamsters, but I do like Graham's concept the best. He's modeled after Alexander Graham Bell, and I think Flurry, while good, is overrated.
I had to pick Graham, because he is my best buddy in my BF's town. He's always been super sweet to me, and was the first villager I got to hang out and dance with in Club LOL too.
I really like Clay's design too though; and I think Hamphrey's cranky face is cute.
flurry is my favourite, she looks like one of those mamegoma seals, though she can look a little creepy, and i guess slowly my love for her is wearing off. i also think clay is unique but i wouldn't say he's in my favorites, most hamsters i don't like, especially apple