First off. Halo 3 didn't end. Master Chief and Cortana get stuck in space and then some creepy music plays. That means Halo Reach is just the beginning and that there will be a Halo 4. Lost in space. Heading toward a random planet. Creepy Music? That must mean after Halo: Reach they will come...
I suggest all these (Top is the greatest)
Assasin's Creed - PS3 + PSP versions
Tenchu: Stealth Assassins - PS1 (If you have a PS3 Memory Card it might play on PS3)
Thief: The Dark Project - PC
Batman Arkham Asylum - PS3
Halo: ODST - XBox 360 (I like Halo but not that stealth)
