I'd recommend this tpb, it's really awesome. Written by the great duo DnA, and great art from Paul Pelletier.
Here's the cover:
Here's the plot summary:
Launching out of ANNIHILATION: CONQUEST, Marvel's sci-fi heroes unite to protect the cosmos! Back-to-back Annihilation wars have weakened the boundaries of our universe. Dark gods and monsters are seeping through the cracks, reigning horror upon those still reeling from the recent calamities. In the face of terror, who stands to defend a desperate universe? Star-Lord and his squad of butt-kickers - the modern day Guardians of the Galaxy! You've heard that ANNIHILATION: CONQUEST rocks - the guy at the comic shop keeps telling you to try NOVA - well, now's your chance to experience the glory that writers Dan Abnett & Andy Lanning and artist Paul Pelletier can unleash! All this plus a wise-cracking raccoon and a telepathic dog! C'mon, people, time to lock and load!
Collecting GUARDIANS OF THE GALAXY #1-6.
You should also check out the first Annihilation series, and as Darthphere said go from there, because all those cosmic events are really good. Check this tpb out though if you'd like to dive into the modern GOTG.