If you're buying the lens along with the camera, the best value is going to be whatever standard zoom is in the official Canon kit.
If you already have the camera, the best value would have to be the Shorty McForty. It's still worth giving a shout-out to the Plastic Fantastic, but the Shorty McForty is a significantly better lens for not much more money, and therefore has a better price to value ratio.
If you really want a fast 50, then the f/1.4 wins the day. It's a better lens than the L in virtually every respect for a small fraction of the price.