Signs easily...it was more of a cerebral film and very effective misdirection by M Night Shamylan. Signs isn't really about Aliens or an invasion...most idiots most likely missed that and were pissed off about the "water being the weakness" which isn't really a big part of the film. War of the Worlds had a strong opening, good build up...but fizzled out quickly. If you like to think during and after movies, Signs is for you. If you are into special effects, big giant robots and explosions, War of the Worlds is your pick.