My main man is Nasus, and I still consider him to be my "I want to win my next game no matter what" pick. Still works for me most of the time to, primarily because I just know the champion inside and out.
Very close secondaries however are Cho and Malphite. Cho is my absolute favorite complete kit, since it just feels like it all works together so perfectly with all of his many versatile build paths, and he's a go-to "safe" jungler or top laner for me. Malph was the first champ I ever played, I played him before he was fotm the first time, I still loved him through that and the following nerfs, and continued to play him up to and through his current fotm phase. I don't really even dread the coming nerf anymore. I'll still be a fan.