Visualizing electrostatic potential maps

Every organic chemistry book I have has these really nice red, orange,
yellow, green and blue electrostatic potential maps and I'd like to produce
some of my own and I'm having absolutely no luck.

I've tried in Chem3D (from ChemOffice 2005), but all I can get are red white
and blue ones with very little shading and they're just not very nice. Chime
seems to make them, but they look very pixelated. I tried doing it in
gOpenMol which required me to jump through a hundred hoops to prep all the
data files it needed, only to have it crash as soon as I tried to render the
plot.

What do people use to make those nice plots? I seem to be having a lot of
trouble finding information about how to do nice ones out there.

Thanks.


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