The budget and how I should spend it (Patreon)

The budget is starting to pile up again, so I'm going to have to start thinking about what sales and such I should look into. Yeah, it might be a tad early, but I figure I should get it out of the way.

The biggest issue with my current computer's build is that the motherboard (the big honkin' circuitboard everything connects to) is old as heck, so I am using a bunch of parts that can only fit mobos from that era. My CPU is the current bottleneck, but I'm already using one of the better ones that can actually fit in my motherboard.
If I upgraded to a new mobo, my CPU and RAM wont fit in the new one, so I have to get new parts to replace them, and the power supply inside might need to be replaced for a better one, maybe. Thankfully the newest part in my computer, the graphics card, will work in a new motherboard.

Motherboards of the tier I'd be looking for run for around $120-$150, the CPU would be around $150-ish too and reasonably-decent RAM that's compatible would run for around $70-ish. Rough estimates, I know.
The question is, how much should I rush getting the new motherboard and the basics to get the new setup running? Should I buy a good motherboard, and some cheap parts to fill it, then upgrade it later? Should I save up and skip the drama, going straight for the good stuff? What about the tried and true method of slowly buying parts and keeping them in a closet somewhere until I have the full set?

Semi-related, but I want to replace my computer's case, too, but there's no way in heck I'd make you guys pay for it. If I want a new case, I'm paying for that out of pocket.

TL;DR: Next part to upgrade is the motherboard, but the process of upgrading is pricey. What should I do?

EDIT: poll complete, results are now public.