I own a Walther P22. I picked up the rare pink one for my 10 year old daughter. She loves shooting it. The weapon is fairly accurate and so far has been extremely reliable. We have fired close to 1000 rounds through it and haven't had any stoppages or malfunctions. We mainly run Remington or CCI 22LR cartridges through the weapon.
There is one slight draw back to the Walther P22. They have been known to get slide cracks when running high velocity ammo over an extended period of time. If you do purchase one, keep an eye out on the front part of the slide. That is where the cracking has occurred.
I normally would never recommend a weapon that I know has had a catastrophic failure, but the Beretta 92F is a perfect example. Beretta had some slide failures. It turned out it wasn't the gun, but the ammo that was being run through it. I own an American and Italian Beretta 92F and have put thousands of rounds through both of them and neither of them have any signs of fatigue.
As I mentioned earlier, I purchased the pink one for my daughter so we paid a considerable amount more for it. The average price in my area is under $350, which is reasonable.
There is also a new Sig Sauer Mosquito on the market with is also a semi-auto 22LR. I have not had the pleasure of fireing one of them though. I do know that Sig makes quality products, so you should look into it. There are some early complaints about the trigger pull, so dry fire it before committing to buy.
So, which 22 pistol do I recommend? I would go with the Walther P22 (in pink). Keep an eye on the slide and do not run ammo that is extremely high velocity (try to stay below or around 1000 fps).