If you had asked me this in the 80s & 90s, I would have said "Japan." But today I would probably say "North America" as only Nintendo keeps me buying Japanese games in any significant quantity.
Of course, Japan utterly dominated back in the day, so that was a no-brainer. In addition to Nintendo, Capcom, Konami, and Square were just killing it with lots of quality releases, and even Sega put out some good games.
But as gaming transitioned from 2D to 3D, many great franchises of Japanese origin failed to break through the "polygon ceiling" and eventually faded from prominence, and as genres and tastes changed, I felt most Japanese devs just didn't "get" 3D. Nintendo and Square managed to largely avoid this, and indeed most of the Japanese-made games made in the last decade that I have on my shelf were made by Nintendo. The Japanese third-party software market has become increasingly quirky and niche in a way that usually doesn't mesh with my preferences, and as my tastes for 3D video games developed during the late 90s & early 00s, it got to where most of the games I enjoyed playing were made in the West, mostly America once Rare left Nintendo. Of the 30 current-gen games I have, 13 were made in America, ten were made in Japan (over half of those are Nintendo games), and seven were made in Europe.