ExtremeTech gives some advice on building a LAN party PC, you can check it out over here.
Like any large scale human endeavor, LAN parties have their own set of aristocracy. You've got the hotshot clans, who win at tournament play. You've got the hardware geeks, with their $5,000 rigs, tricked out with lights, custom paint jobs, and esoteric cooling gear. That's fine, let them have the spotlight. You're there to have a good time with your gaming buddies.
Of course, you probably don't have $5K or $10K to spend on a Killer Gaming Rig. Even if you did, the thought of lugging around 65 pounds of fragile computer is pretty unappealing. So can you have LAN Party bliss on a budget, without breaking the bank or your back?