Its all depends on your needs.
I am also at the beginning of my journey at lego technic world. In the late future my goal is to build some TATRA track from free instructions at rebrickable. At the moment Im not decide exaclty what tatra i will build, but every rc vehicle 8x8 has many different motors (xl, l, m) and power source (buwizz, battery box, etc).
Good startup for any rc is 42095 which i just bought, probably in the near future i will buy another one because its profitable, but im also collecting XL and m motors. 2 x led lights at start will be enough also, 1 for the front, and one for the back.