first thing i'll do is start with the first few missions, to get a feel for the game and some of the new features. then i'll go out and explore for a bit.
wait... has someone already posted something similar?
oh, man. i know i'm going to be so excited, i'll just start running around the neighborhood, breaking everything i see. knocking down every pedestrian in my way, and kicking every cop in the nuts! then i'll come back home and start playing gta 5.