Maxim spent some time with legendary Mortal Kombat announcer Hernan Sanchez, during which time they did exactly what I would do in that situation - make him say silly things in a menacing voice.
Mr. Sanchez has one of the most recognised and authoritative voices ever put to work in a video game, so when you hear him say, for instance, "Epic Fail", you truly feel like you failed on a rather epic scale. Conversely, when his deep voice rumbles your speakers with "Flawless....Ensemble", you can't help but feel like you've really made your outfit come together.
Maxim was kind enough to make an embeddable version of their Unlocked Mortal Kombat Phrases soundboard, which I have been kind enough to embed, after the jump. Enjoy!