A good way to scroll through stories is the "Table of Contents" at your right =>
Fantastic Four #48-50: The coming of Galactus
The first appearance of the Devourer of worlds. A classic tale collected and re-printed multiple times.
All three formats are great depending what you prefer.
Silver Surfer #1: The origin of Silver Surfur
Galactus' second appearance is the origin of Norrin Rad. It is a great book with a very compelling story and a good look at Galactus' personality.
Like tCoG, it can be found in the Essential line and the Masterworks line.
Fantastic Four: The trial of Galactus.
One of Galactus' best stories. In this story Galactus returns to earth after his new herald Terrax poisoned him and tries to kill him. The Fantastic Four try to stop Terrax and save Galactus from death. As a result Reed Richards is put on trial for his decision. Also Galactus' new herald is born. The story features a great insight on Galactus and its impact and consequences are felt even today.
Collected in the homonymous tpb. Fantastic Four issues #242-244, 257 and 262.
Fantastic Four #74-77: When calls Galactus
Galactus' second appearance on the FF title following the events of tCoG. Galactus returns to earth to make Silver Surfer his herald again. The FF try to save the SS but Galactus threatens them with the destruction of their planet.
Like tCoG, it can be found in the Essential line and the Masterworks line. The omnibus collecting the story will be releashed April 2015.
Fantastic Four #204–214: In Search of Galactus
The earth is threatened by an egyptian god, and only Galactus can save it! This story is great for showcasing Galactus' might. Also the first appearance of Terrax Galactus' new herald. A very good story by great creators like Marv Wolfman and John Byrne.