My '07 Prius hybrid battery died today at 169,000 miles. I am not the original owner, but have put over 100,000 miles on it in 5 years. I researched and called around and it is what it is. It will cost just under $3000 to have it replaced.
There was no warning, just some scary dash lights that I have never seen before when I was leaving the parking structure at work. When I looked in the owner's manual it said that it was brake related, but I had new put on last year so couldn't believe it was that. I called the dealership and they said I could drive it in. As I drove, I heard a noise coming from the back of the car, like static. I put on my hazards and drove slow on the freeway. Acceleration got worse the further I drove. Just made it to the dealership and was shaking from the stress. No replacement in stock so I have to rent a car for a day until it can be fixed.
I didn't feel as bad when my dad told me his Honda hybrid has had to have the battery replaced twice. He has had it for a long time, though, and has over 200,000 miles on it.