All of the above is great advice. I've leased 3 vehicles and fortunately, each has turned out to be a good experience for the most part. Definitely don't lease if you put more than the typical 12k - 15k miles per year - that will REALLY get you in the end when it comes time to turn it in.
Leasing will get you into a "better" car for the money when comparing purchase vs. lease. However, if you are thinking you'd consider buying your leased vehicle after the lease, look at the contract about it's residual value and purchasing fees - many times you'll end up paying more for your own vehicle than if you'd bought a similar used one.
Also, you really do have to keep the leased car in VERY good condition. The leasing banks will stick it to ya for dings, scratches, stains, tears, cracked windshields, rock chips and tire condition at time of turn in. If you have kids and can't garage the leased vehicle, you're already running an uphill battle...
My best lease experience with with my '02 Dodge Ram Cummins 3500. Leased it for 4 years, and my residual value was going to be $18K and change. These trucks really hold their value and when my lease was about 6 months from the end, I went shopping to compare new trucks vs. buying my '02. Turned out that my '02 had a re-sale value of $26K!!! I was ahead of the game either way - buy it for $18K and have equity, or take that equity and put it down on a new truck. I bought a similar '04 truck in March '05 (caught a year end close out that wasn't moving) and now have brand new paying only 2/3rds the dealer invoice.
Worst experience was a '98 GMC Jimmy. 5 year lease, residual was $16K and current market was only bringing $13K at best.... and ours only had 35K miles on it after the full 5 years. These Jimmy's are a dime-a-dozen so this meant no equity to put down on a new purchase. We started the lease already upside down on our trade in and financed $3k into the lease.... HUGE mistake. On top of that, the leasing bank tried to get us to pay $1800 in "excessive wear" to the vehicle - rock chips to the hood paint, a ding on the rear bumper and a peeling decal....... We had to fight for 3 months to get them to realize that in Colorado, rock chips are unavoidable, the ding was the ONLY body damage on a 5 year old vehicle, and the decal was an unreasonable issue. We had to harp on the fact that they were getting a vehicle that was 40K miles UNDER what it should have had at lease end.... we won that one.
If you do end up leasing, the best advice I can give you is TAKE PICTURES OF THE CAR THE VERY DAY YOU TURN IT IN AT THE END OF THE LEASE! This saved our ass on the above mentioned Jimmy because our pictures showed that the smashed rear bumper on the Jimmy when the bank received it from the dealer, wasn't there the day we turned it in. The "ding" was a 1" circular dimple in the bumper, but the leasing bank said the rear bumper was pushed in, folded and needed replaced. The leasing documents did say that we agreed to turn the vehicle over to the bank directly at the end of the lease, but the dealership said they'd take care of the delivery to the bank..... a common practice, but you can see how you could be hanging out with having not followed the agreement.