It entirely depends on the mood you want the quilt to have.
Brown, pink, and yellow would be a soft, warm, calm analogous scheme (colors next to each other on the color wheel). Brown is actually just a saturated orange.
Brown, pink and green would be a more contrasting complementary scheme (colors opposite each other on the color wheel) which has added zip.
Brown, pink, and turquoise is straight from the 50's and would give the quilt a very retro feel.