There are a number of advantages to leasing in the US but they invariably depend on the buyer/lessee's circumstances, wants and needs.
One benefit is that you can typically "afford" to drive a car you might not otherwise be able to own. With a loan you're paying the full price of the car over a period of years (typically 3-5yrs); whereas with a lease you only pay for the predicted value of the car you will use over the period of the lease (e.g., 40-50% on a 36mo lease w/15k mi). Generally speaking, the monthly payments are significantly less; especially when there are factory incentives built into the lease rates.
If you are the kind of person who has to have a new car every few years then another benefit is that the cost to you over the course of a 2-3 year lease is generally better (read: less) than the pay-off amount left on a loan.
Another benefit, closely linked to the first example, is that you don't have to worry about a down payment and, in fact, as noted in earlier posts you should avoid any additional cost reduction through the equivalent of a down payment. This allows you to free up capital that you can otherwise use for investments or other needs over the short term of the lease.
Yet another benefit, at least in some states where property taxes apply, is that you don't have to pay tax on the value of the whole car. Often the tax is only applied to the monthly fee. There are also sometimes tax breaks if you own a business and can run the lease through it.
Just a few things to consider. I may have missed something and I am sure someone will chime in with other thoughts, Whether it makes sense for you is an individual question. The key to leasing is doing it intelligently. Know the terms. Know how to negotiate a lease or learn how. Know what you're getting yourself into. And, most importantly, know what to avoid and run from.
My $.02,
-Eric