Siri on iPhone 3g

[///ViNcE]

It is technically possible, there's just no real need or desire for anyone to do that sort of thing, so you don't see it, it remains "to be seen".

You could have apps out there in the future though that delete all of your data.

Or perhaps act just like a Keylogger or RAT for retrieving data when you use WiFi for people that do quick online banking?

There's always possibilities, it's just highly unlikely at this point. And since apps get filtered through iTunes from my understanding anyways, it's less likely that a "malicious" one of any sorts would get through.

True, but also watch out with the other Cydia Apps, people jailbreak their iPods so they can release third party apps that actually modify part of the iOS that Apple doesn't allow.