For Tamiya kits, I use Tamiya paints and rarely substitute. For every other brand of kit, I use Tamiya paints. I used some Gunze Sangyo sprays once, and they were good, probably better than Tamiya, but not enough to pay $3 extra.
I usually buy one spray can per model for the body color, and use the bottled acrylics with either a brush or airbrush for the rest.
For the Tamiya paints, I keep buying the 23 ml bottles, and most colors last forever. The one that I always have to go get more of is X-18, Semi-Gloss Black. I go through that stuff like water. Otherwise, I'm getting to the point where my paint box has most everything a kit would ask for, barring any "special" colors.
I hated working with enamels, and have mostly stayed away from lacquers.