Of the ones you mention, the most likely are Netflix, Hulu, YouTube and Safari. That's because there are clear precedents in place with those providers that would most easily allow them to be ported to a new platform.
Netflix is the most obvious of the bunch, since Apple already has a very successful relationship with the service on the existing Apple TV. I'd also guess that Apple would be keen to offer users access to Safari, at least, if not Mail and other basic iOS apps.
As for a bult-in tuner, that might be less likely. Apple is probably going to want to do its best to control the ecosystem on a new television product, just like it does currently. Revenue will depend on content sales, and an OTA tuner could take away from that, and disappoint any content partners Apple brings on board.