I don't think there's such thing as short-term purchase. I mean, everyone needs a car, or else you keep standing beside the road with your thumbs up. Leasing a car could be a good idea, but if you can afford to buy a new one then why not try to purchase.
I leased a car once and only once because it only makes economical sense under certain conditions. At the time I was in sales and used the car for work and I put lots and lots of miles on it. Therefore I could write automotive expenses including the cost of the lease off my taxes as a business expense. Unless you can justify the expense as a tax write off, you're likely to come out on the short end of the economic stick.