Mass Effect is a bit of a weird name. I understand that it's the name given to the effect of Element Zero, but that's kind of like naming the Sonic games 'Newton's Laws of Motion' or 'Forward Momentum', or calling Portal 'Heisenberg's Uncertainty Principle'. I guess the great thing about a name like that though is that it tells you nothing about the game. You don't associate it with anything but the game itself.
Worst game name I've ever heard though is, "Irritating Stick!" oO How can you go beyond that? Irritating Stick!