Windows 10. I'm mostly going to be doing pamphlets (think playbills) and large-format posters. In-line text editing just isn't cutting it these days.
Bonus points for open source, extra bonus points for release on both Windows and Linux, and SUPER extra bonus points for simple integrated vector drawing. Native SVG support would be excellent for putting together large-format projects (raster scaling :P) and things with lots of infographics.
I'm ditching Publisher because my license for it is through an organization that I'll be departing fairly soon, and I'm not in a position to pay for a new one. For the same reason, I'd prefer to stay away from a subscription model. I could commit to a one-time purchase in the ballpark of $30US, if it came to that. I highly value configurability and active development, so open-source applications are always preferable, but that's not an especially high priority in this situation.