Generally, most of us get the safety stuff first (brakes, rubber fuel lines), then reliability stuff, then personal choice as to motor, paint or interior updates. several full-on make-overs here too.
Like Dave said, depending upon your plans for the car, your purchases and $$ spent will be different.
Welcome! Radial tires and brakes is what I did when I got my '65. However it does depend on what you got and budget, for instance a new radiator had to be top of the list for me. Good luck and the more work you put into the more enjoyment you will get out of it!