Also remember that, while it isn't indicated in all mentions of negative levels (such as the Enervation spell and the MM), each negative level results in -5 hp, per the DMG/SRD "Special Abilities and Conditions" sections on the "ENERGY DRAIN AND NEGATIVE LEVELS" ability and the "Energy Drained" condition, which I consider to be the controlling definitions. So, you might die even before your negative levels equal your positive ones, though in that case at least you won't become a Wight.