Tough choice. My first thought was the SNES, but on reflection I might have to go with the Xbox 360.
I'd have my Halos. I'd have my Resident Evil C:V, 4, 5, 6, REvs 1, and 2. I'd have Morrowind and Oblivion (and Skyrim I suppose but its only real purpose to me would be making the others look...