Two more aspects to consider when leasing....
In this thread I see references to a 39 month lease. Keep in mind that the vehicle warranty is 36 months.
I read an article a few years back on edmunds.com which strongly suggests either getting the warranty extended to 39 months or the lease reduced to 36 months. If something substantial breaks in the 37th month, you will likely be on the hook to cover the expenses to get it repaired prior to returning it at the end of the lease. Some negotiation may be possible if you are leasing another vehicle from the dealer.
I have followed this suggestion each time I leased a vehicle and it removes those repair concerns for the last 3 months of the lease. I leased a car for my daughter and the cost to extend the warranty another 3 months was negotiated to $1.57 per month. They wanted a lot more, but I was willing to walk away (politely) from the deal so they sold the extended warranty to me at $1.57 per month which I believe they said was their cost.
Also, I recall (vaguely) a conversation with a sales manager when negotiating a previous lease. He pointed out that it is best for the buyer to lease at the beginning of the model year, and not as good at the end of the model year. He pointed out that if you lease at the end of the model year, like it is now, they consider the vehicle to be 4 years old when it is returned which reduces its residual value. The lease is based upon the difference of the sale price and the residual value. But, sometimes if a dealer has an excess of a particular vehicle at the end of the model year, so you can get a great bargain. Don't be mislead.... just because you lease, doesn't mean you can't negotiate the sale price that the lease is based upon. The edmunds.com article suggested closing the deal on the last saturday of the month, or even better, the afternoon of the last day of the month.
For those who haven't leased before this might also help. The concept of leasing became clear to me when it was explained that when leasing, I agree to purchase (it's not a type of renting) the vehicle from the dealer at an agreed price. Then, 36 months later they agree to purchase it back from me at the agreed upon price if it is in acceptable condition (no repairs needed and acceptable mileage). IMHO, the attractive parts about leasing are that the monthly payments are about 35% less than purchase payments, the lease payments are made for 36 months while purchase payments are made for 60 months, the vehicle is ALWAYS under warranty while I have the vehicle, and I get to drive it while it is fresh and hopefully problem free.
In response to another previous comment in this thread. All down payments on a lease are lost in the event that the vehicle is destroyed or stolen (not recovered). I have never put money down on a lease, but sometimes have had to make the first lease payment up front.
Those were a couple of thoughts that I thought might be worth considering. You might be able to tell that I advocate leasing. Sorry if I sound too biased.
White Bear Lake ... in Minnesota
BTW, I don't have my Leaf yet. I contacted a couple local dealers, and I am hoping a dealer will make an attractive offer during the Labor Day sale next week. If not, I will patiently wait for the 2013. So if there is a dealer reading this... I'm ready.