I think my answer would have to be Alinor. I have 7 characters and most of them move around regularly based on what they're doing at the time, but my crafter is the exception - he only leaves the city to do surveys and buy stuff from traders so the majority of his time is spent in Alinor.
It's actually a lucky coincidence that Alinor has a convenient layout for crafting. I moved him there because his backstory is that he's a retired soldier who wanted to move somewhere quiet. He lived in Vulkhel Guard for years before moving to Alinor when they opened the borders (aka when Summerset came out), but I'd have done that regardless of the crafting setup. Unless of course it didn't have writs or crafting stations (or a bank) because that would make it impossible.
Most of my other characters do have a "home" city they go back to more often than any other single location, but it's still only when they're moving between areas or activities, otherwise they just go to the closest place with the services they need. Like my crafter they're all chosen for story reasons rather than gameplay.
For my khajiit (who left Elseweyr when the Dominion moved in) it's Evermore.
For my breton it's Daggerfall.
My argonian lives in Bal Foyen.
My dunmer (who moved to Summerset as a child) is currently based in Vulkhel Guard but at some point will move to Alinor.
Then my nord and bosmer don't have home because they move around too much - The nord is a mercenary (aka tank I only use for dungeons and events) and the bosmer...tends to upset people if he stays in one place too long. There's only so much unexplained death the locals will tolerate.