I am just about to turn in a leased '01 S80 2.9 with 42K miles. Has every option except Navigation system, and 3 month-old set of tires (17" Arrakis wheels). Back seat was used three times in four years. No children or pets. Washed once a week, and waxed every month. All required maintenance done by local dealer. Residual value on the lease contract is $18.5K, but Volvo finance North America has phoned and offered a price of $17.5K to buy it outright.

Without an effective warranty, no thanks. A great car to drive, but parts are way to expensive. You can virtually count on the following items to fail every 30K to 50K miles:
Throttle Module (~$1000 to fix)
ABS module (another ~$1000)
Oil pan O rings
Stabilizer bar links
Spring seats
Front suspension members
Door switches (false alarms; won't lock)
Steering wheel module (SWM)
Upper electronics module (UEM)
Various Lamp sockets
Every exterior light bulb at least twice
Brake rotors

There have been sporadic transmission failures as well.

Figure on spending $1000 a year on unanticipated repairs, plus another $250/yr on regular maintenance, unless you do a lot of your own work. If you keep it long enough, you will need a timing belt replacement as well.

For about the same total $$ as depreciation plus repairs, over 4 years, you can lease a brand new one with a 4 year factory warranty.