We've had two Priuses -- a 2001 that we bought in 2005 and a 2007 Touring that we bought in 2012. We still own the '07, and just got back after driving it to dinner. It is my wife's daily driver, and she wants to keep it forever.
We replaced the main battery at about 140,000 miles four years ago. I found an indy Prius specialist who brought a factory Toyota battery out to my house and replaced it in my driveway for $2800. I think his labor and mileage was about $300 of that. There are refurbished and aftermarket batteries available for less than $1,000 but this is my wife's car, and I didn't want to cut corners. A handy person, if so inclined, could DiY the battery in a couple hours.
The one annoying failure with the car was front wheel bearings. We're on our third set. Other than oil, gas, trans fluid change every 50K, wiper blades, I changed the spark plugs at 120k, and struts at 150. It got a Walker muffler about the same time as the plugs.
The 2001 model, I didn't like. It was a tin can -- a reliable tin can, but no pleasure to drive. I still see a few of the Gen 1 models around in my area of southern Wisconsin once or twice a month.