Sorry to burst your bubble- but a friend of mine forwarded me a (non-classified) report from the folks that build them. An RPG round in the right spot will penetrate the flank armor and set the hydraulics on fire. Also, a good ol' Molotov cocktail on the engine deck can set it on fire. Also, 25mm depleted uranium rounds (like from a BTR's or BMP's autocannon) will likewise penetrate the flank or rear turret armor at close range. I would guess that a sabot round from an ex-Soviet Rapier 100mm antitank gun could also do the trick. The Abrams is the best tank in the world, but any tank is a tradeoff between speed, armor protection and firepower. The Abrams will do almost sixty miles an hour flat out and fire accurately while doing it. IMHO we need a slower, cheaper, much heavier armored tank for urban warfare.
IIRC - At Kursk the Soviets rolled their big, heavy, slow, un-maneuvrable, very heavily armored tanks (K7? T7?) into the middle of the fight, parked there, and blew the sh** out of the Germans. There does seem to be a time and a place for everything.