It's been debated ad nauseum in the garage...
But in a nutshell, there is no real replacement fiscally for buying a reliable, modest priced car (new or used, price and expected life is key here) and driving it for 10+ years.
That being said, if you have disposable income and routinely like to be in something different every couple years then leasing is reasonable option. Between lack of maintenance, updated fuel economy, saftey, options, ect it's a way to stay in the latest and greatest without losing your ass on trade in values.
Plus some lease deals are simply more competitive than others. It's hard to argue a $199 a month, low money down lease on a decently equipped Accord or Camry assuming you are within the annual mileage allowance. Most of those types of leases are nothing more than 0% financing over the length of the lease and depending on the buyout of the vehicle you can buy it outright for a very reasonable amount. The only catch is state dependent and how they handle sales taxes on leased vehicles.