Green Car Congress news brief - Only worthwhile quote: "A major restriction to lead-acid battery efficiency is the lack of interface area between the active chemistry and the electrodes. Although the chemistry is theoretically capable of delivering approximately 170 Watt Hours per Kilogram (Whr/kg), lead-acid batteries only average around 30 Whr/kg."
French CEA article - on leadup to Li battery. Has energy density numbers for lead acid, NiCd, and a history of Lithium batteries
energyadvocate.com page with energy densities for 7 (not necessarily rechargeable) batteries. Cites Professor John Tanaka, University of Connecticut, Dep't of Chemistry.