Final Fantasy. I've always meant to at the very least play FF7 but haven't gotten around to it, and JRPGs don't really appeal to me (other than Ni No Kuni, but that's mostly because it's a Studio Ghibli game)
Metal Gear Solid. I remember trying to play MGS on PS1 back when I was a more fickle gamer and couldn't be bothered with stealth. I played through the first three acts of MGS4 but stopped after that return to Shadow Moses bit and told myself I'd start from the beginning, especially because I was so confused, but still haven't gotten around to it.