I've only leased once in my life, and I don't anymore because it effectively ties you to selling the car back to a single party at the end, at their time frame, on their terms. Yes, I know that technically you're just "returning" the car, but in fact, the dealer or leasing company has the right to charge you above the payments for any damage they find or excess milage, etc. So there are only two reasons to lease, IMHO:

- when you do the financial analysis the lease offers a more attractive NPV then purchase. This could be because either you and the lessor have a different view of what the fair market value of the car is at the end of the lease, or because the interest rate they are charging is - on a risk adjusted basis - lower than what you would earn on the money (remember that stocks can go down as well as up).
- if you don't have the available cash.

Otherwise, buy.