For me, my shop is a sort of perpetual project. Seems there's always a cabinet to build, something to organize, a work area to make more efficient, or even just plain clean up.
I tend to bounce between shop projects and furniture projects. I like to find a challenge and pursue that, for example, I've been into bow front tables lately. I'm on my second small table and first large table. Its been an exercise in pattern routing, odd joinery and veneering.
I can't tell you what to build, but I get ideas from around the house - end tables, maybe a dresser, maybe to replace some store bought cheap stuff. They will be family heirlooms.
Chip carving is something else I got into merely for diversion, and I fell in love with it. Its a good side trail to take away from the noise of the shop.