Voted for Chemistry.
I love Signals. At the moment I'm listening to it the 3rd time this day. I could pick Subdivisions, The Analog Kid, Chemistry, The Weapon or New World Man. But the other three songs are also excellent. In the 90th The Weapon was my favourite. Now it's perhaps Chemistry. Sometimes I'm dancing through my apartment when I hear this magic song. It's so exciting and beautyful, and it contains one of Alex's best guitar solos.