I base by squad and by genre.
Anything that might end up in Mega City One gets grey fairly plain bases with some mechanical blocks or rubble ... but minimal.
My Blakes 7 figures get dirty grey with lits of dirt. The show used to be very often in an industrial or rough looking environment.
Fantasy gets green mainly but with varying browns and dirt.
My historical will be the same as my Fantasy
I dont have a gaming mat so bits of scenary are placed on the table ... either black or brown is the backdrop.
I love the new lipped bases and I am going back and retro fitting my figures with them.
I think the key is to have the squad or set of figures to look cohesive together. So the genre dsetermines the overal look whilst each squad of figures will get based at the same time.
Apart from that I recommend being totally chilled out over this. We are playing a representational game ... its not real and the more relaxed we can be about it the healthier for all of us!
Nicely painted Gronk up there by the way