If you have the money to buy a new Lanber then do so they are one of the best budget guns on the market and you will get your warranty. However if you can find a well looked after shall we say, low milage Beretta then that will be a slightly better buy but both will last you years if you look after them properly.
I have had both and been very pleased with both.
My personal choice would have to be the Beretta,686,687,682.
But make sure you get one to suit your eye dominance, that is to say a left handed one if you are left eye dominant and learn to shoot with it. It will feel odd at first but two weeks later you wont notice it if you practice dry mounting each day for 15 mins, it will help you shoot better.If you are right eye dominant or middle vision then buy a right handed gun.
Also don`t forget to buy some snap caps, most people do.