I voted for Winterhold. Yes I know it's just a cluster of buildings and some ruins and the College. But I love the snowy atmosphere and the location on cliffs by the sea. And when I go there I often imagine what it looked like before the Great Collapse, when it was the center of power in Skyrim. And also daydream about when mods might make that true again.
I can't stray too far from Whiterun. With my house, a smith and general store all right next to one another, I rarely have to go far to do my things. A second favourite would be Riften.
While I own the house in Solitude, I've always loved Falkreath and its hold. It's such a peaceful little town, with beautiful pine forests and great weather. Not to mention I love its colours and heraldry.
I chose Riften with Windhelm being 2nd and 3rd being Winterhold because of the area north of there.... I love the blizzards and the feeling of being lost up there.
Riften, so much to do and the area around is just like Colovia(North of Riften) nice forest and with the huge mineral geyser area north of there just so much fun.
Windhelm, Snowy parts and the populace hates me so I like killing a few of them at night only when I'm in a good mood. Also the same reason as Riften except to the south