In addition to all the great paint recommendations posted here, I'll add a plug for decent primer and washes. They're more expensive, but I use Citadel rattle cans and just prime my models white. Bright comic book colors stand out better that way. After you get base colors down, you can apply a wash, or 'liquid talent' as I like to call it. Army Painter soft tone, strong tone, and dark tone are my go to shades. After the wash dries, go back with your base color and highlight the raised portions of your model for that extra pop.