I want to say: Steambox presentation with Half Life 3... Okay I'll start being serious now. Steambox presentation with either Left 4 Dead 3 or Portal 3. That would be pretty sweet.
Final Fantasy XV Kingdom Hearts 3 Gravity Rush 2 Persona 5 Project Morpheus Mirrors Edge 2 (with Rift/Morpheus support) Ratchet and Clank PS4 Final Fantasy Type-0 Vita/3DS The Last Guardian Beyond Good and Evil 2 PS4 support for PS2/PS1 in native HD (rumored) Some of that is more just wishful thinking though.