Before I begin, please take a moment to add some additional information to your profile.
Anyways, for your first gun I suppose I would recommend an AEG, so the mp5 would be the pick. The reason for my choice is that often when your in a game, you will be using your Primary more than your seconday, and as someone just getting into airsoft, the best thing to do is to just get out there play and see how you like it and then built your kit after. Thats the short answer atleast.
"Its only a little bit on fire"