The most important single question about the G major chord (standard tuning, of course):

Do you use fingers 1-2-3 (middle finger on low E string, ring finger on high E) or fingers 2-3-4 (ring finger on low E, pinky on high E)?

As much as any single indication, the method you employ to make the "G" serves to separate the amateurs from the "playas."

The 1-2-3 version is taught to beginners, but the 2-3-4 fingering is far easier to use in most situations ~ especially in the key of C ~ for quick chord changes, bass runs, etc. The only case where I can see the 1-2-3 formation being preferable is in two-chord songs in G, where the only chords you make are G and D.