What tools do you already have, and what's your budget?
I've operated a few excavators, and they're nice for moving lots of dirt. I personally prefer backhoes, because they don't need to be trailered everywhere which makes them more versatile, and cheaper to operate. Doing backhoe things with my backhoe:
https://permies.com/wiki/50/99575/pep-earthworks/Scoops-Excavator-PEP-BB-earthworks#2003033
My lathe is probably my favorite tool. I think I paid $1200 for my old South Bend lathe.
I've had a drill press for a long time, but my magnetic drill press is amazing, because it's so much easier to drill things that don't fit in the press. Plus it runs really slow so you can feel when the drill bit starts trying to pull through, which prevents a lot of drill bits from getting broken.
I already have a couple of welders, but I'd really like a plasma cutter.