Well, it isn't too far fetched.

We already have 3D environments such as Second Life or the Sims where we can control our virtual avatar and do tons of stuff. Most people have a recent cell phone which can handle applications, if you have a smartphone or pda you have even less limits, and you can connect to pretty much every device that has bluetooth or wifi.
As for interaction between man and machine, there are robots in Japan with an AI so sophisticated that they can respond to human speech, movement, touch and recognise facial expressions.

On the other side, cyber criminals aren't something new, they've existed pretty much since the dawn of the internet.

well nothing u can really do about cyber crime, it will happen whether we like it or not, but if Japan has advanced that much, then i dont see it being that far into the furture,  PET's seem like they can easily b made today, my only concern would be the A.I.-but there have been reports that this is advancing quickly and that it is currently an application used by the U.S. military forces overseas.

well if you count the new ipod that talks to you, then it can be a PET. But i dont see actuall PETs being made or navis. I would totally make one. which brings another question... What would your navi be called? what would it look like? can you customize it? will there be a way for it to actually take down a virus? Chips wouldnt be called battle chips though. just virusdeletion programs...er something.

Well as of now, it doesn't seem possible but if there were real net navis, I would be totally psyched to have a PET.

it for the most part is quite possible but it would be like colonel in  the anime when barrel took out his emotions.The customazation process cannot be that hard if it's made i mean seriously there could be an online thing were it's made to your taste like phantasy star portable has a charactor creator.then if it gets really advanced(or really well hacked)we could start having videogames where on the player select screen your navi can be played (hopefully a built in feature in the game or else you would have to write in your charactor data and that would vary per game and be a pain)the emotions part is the only thing I see as immpossible on todays equipment.but when they first come out you may have to say "open email" not "hey mega can you please open up my email"and also until voice recognition is really advanced you would have to be in a pretty silent place.