Depending on what I am doing, what I use:
PRIMER: Tamiya gray and white primer - always warmed before spraying directly from rattle can
PAINT: Testors, Humbrol, Model Master and nail polish - always warmed
CLEAR: Wet look clear
THINNER: Lacquer Thinner for thinning enamel for airbrush and cleaning airbrush and brushes. Mineral Spirits for thinning brushed on paints and washes.
WASHES: Mineral spirits for enamel paints, alcohol for inks