Whitney for sure. I love her. I had her in all my towns so far <3
Also i really really have grown to Wendy. I usually dont like peppy villagers that much, but she doesnt bother me at all.
In my town Maple is my best friend since she's been there longer than the others and she gave e her pic, shows up in my house unexpectedly, etc. but I just got Aurora back and she will be my best friend because she and I go waaaaay back
Pietro would probably qualify as my "best friend" in the game. He's my mayor's next door neighbor in my main town, he has the Smug personality (which is my favorite), and the letters he sends are pretty entertaining. He also fits the theme of the town, that being horror, since a lot of people seem to be terrified of clowns. I'm personally fine with clowns, but it adds to his appeal.
It's likely safe to say that I'm happiest to have Pietro the most of all of my dream villagers, with Ribbot being the closest competition. It's Pietro's personality that just edges him over Ribbot.
Definitely Julian forever. :3 He was one of the first to move to my first town and we played around all the time. I mean, he's a unicorn!! Freaking awesome best friend unicorn, how could you not love him