Interesting article here
http://www.newsweek.com/id/138808/page/1
"For those unlucky few who have to replace their own batteries, the cost is coming down. On June 1 Honda is slashing the cost of its batteries from $3,400 (excluding installation) to as low as $1,968 on an Insight or as high as $2,440 on an Accord hybrid. Toyota also plans to substantially cut battery prices, which now stand at $3,000 (excluding installation), down from $5,500 on the original Prius. Both automakers attribute the price cuts to improved technology and lower production costs. But some analysts think Toyota and Honda are really trying to get ahead of consumer concerns about battery replacement. "
PR is a very important factor in the hybrid market," says J.D. Power's Omotoso. "Honda and Toyota have the oldest hybrids on the road. And when a hybrid gets to be that old, you have to factor battery replacement costs into your purchase decision."
So those with dying/dead out of warranty batteries could hopefully now afford a drop in replacement.