I'm gonna go with the TIE Defender. Overall a beast mode machine that could outmanuever, outshoot and overpower pretty much anything the Rebels had. Shields, Ion cannons and lasers as well as launch tubes and a tractor beam, this beast could take on cap ships as well as starfighters and have a high survivability rate. If the Empire had produced these earlier the war might not have gone the same at all. Then again the Rebels had Wedge, a pilot who was so badass he didn't need the Force.