The interest rate when you leased is probalby higher than what you can buy it for now. My credit union for example offeres 3.99% up to 72 months.
If you will be close to your mileage at the end of the lease term, often times a dealer will negotiage an even lower price than originally listed as the residual price. Especially with this economy dropping. I know someone who leased a Volvo S80. When she was in her last month, they offered her the car for $6k less than the paperwork listed for a buyout price. But, if you drive a lot of miles, it may not be worth the risk to wait. If you buy the car, the dealer has the advantage to either make you pay the full price, or turn it in and pay for the extra miles. Ball in their court. Even miles ball in your court.
I drive high miles and always lease. I lease my cars out for whatever miles I think I'll be driving each year (about 20k/year) and then just turn in my car at the end of my contract (4 years) and lease out another.
This way I pay a lot less per month for my 2004 IS 300-- a car which will depreciate quickly because of the high miles. I'll never keep my cars for more than 3-5 years because of this, so for me leasing makes much more sense. I really don't ever plan to buy my car. If you plan to buy your car when leasing it, just make sure you are close to the end of your lease period
What many people don't realize is that you can lease a car for as many miles as you want...for a price of course. You will pay a little more monthly to pay down on the depreciating residual but will not have to worry about paying for miles at the end. Just don't trade your car in early!That is when you really get hit hard with paying off the residual.