One of my favorite Galactus stories is
SILVER SURFER: PARABLE by Stan Lee and Moebius.
I also love the NOT BRAND ECCH story that parodies the Lee/Buscema origin story, where Galactus is a space-faring discount retail wheeler-dealer, and instead of silver, he wraps Norin Radd in Saran-wrap!
Also, of course, the first Galactus story in FANTASTIC FOUR 48-50, and "Worlds Within Worlds" in FF 74-76.
