HI!
Geckos make great pets as they usually have a funny individual personality.
If handled gently and the gecko is used to being handled they don't normally bite. Its usually best to get them used to your hand and then being handled. They have like a serated edge to their mouth rather than teeth which nicely scrapes the skin off your hand/fingers. Only had one gecko do that to me so far.
The only times I've been bitten is when I've been feeding them by hand and my finger gets mistaken as part of the prey. Made me jump a bit the first time.
I agree with nigel. They very rarely bite.
The only reason why the gecko that bit me did so was because it was probably stressed out due its environment. I go to an animal care college where we keep quite a few reptiles which get handled regularly. This can have a possitive and negative affect on them. Some have become very friendly and love being handled and others hate being handled.
The leo i picked up hated being handled due to the many hands which constantle bonbarded his cage.
I have a leopard gecko and it is a perfect pet for me she is so gentle she loves being handled but at first when you get them they have to get used to you. i have never been bit by a leo they are soo gentle.