As flagamuffin mentioned below, Berlin certainly fits the bill of inexpensive living coupled with a disproportional creative and artistic population. It's own mayer coined the tagline "poor, but sexy" in the late 90s, and since then Berlin's allure as a city on the bleeding edge of art and culture has only grown. Here's an Australian musician who moved with her band to Berlin describes her first few weeks in the city in the NYTimes:

In the first few weeks, we met fashion designers, photographers, illustrators, filmmakers, writers, other musicians and dozens of miscellaneous expat misfits who escaped to Berlin for a clean artistic slate. On encountering an El Salvador-born, Los Angeles-raised filmmaker named Nehemias at a park gathering, I was curious to know his personal motivations for moving to Berlin. He told me about the inexplicable energy he felt when he visited the previous year on vacation. Still in awe of the city myself, I asked if there were any drawbacks to living as a creative in Berlin. “In L.A., people actually get stuff done because you’ll go homeless if you don’t hustle. Here you can be super poor for years and still live comfortably.”

Berlin's also known for it's club scene, which is often linked to it's art scene, so take that for what it's worth. Berlin's also probably more associated with music and the visual arts than writing, although I'm sure there are more than a modest amount of literary clicks in the city too.

Aside from Berlin, Brooklyn in NYC is a tempting answer, but the rent is high and only getting higher. I've heard rumor's from a few people that Hanoi is becoming a destination for western migrants/expatriates, particularly writers, but I can't substantiate them at all so take them with a grain of salt.

EDIT: I just saw that you said that cities aren't really your scene, sorry if my post is useless now :) Isn't the city aspect a big part of the "Paris of the 20s" though?