Don't get me wrong, playing with your friends while in the same room is INSANELY FUN. Seriously they are a lot more fun than Internet+VOP can ever be.
But LAN parties aren't my thing anymore unless we all have gaming-worthy laptops
Carry in your tower + monitor + box of stuff (keyboard, mouse, cables, etc.). Which can be a real pain depending on where you friend lives: in an apartment, where you have to park 100 meters away and then take the stairs. Sometimes make multiple trips.
By the time you bring in YOUR stuff and wire it up... a fair amount of time has gone past. Then you have to factor in doing all of that in reverse when you want to leave.
And if you're HOSTING then it's still a hassle: clean out an area large enough, setup a router nearby, find enough tables and chairs, clean up afterwards, etc.
Again: all laptops is easier. Just a backpack, power brick, and mouse. But I don't spend that much on my laptops.