I got this question just the other day - "What do you think I should sing for Company X - what do you think they want to hear?"
I have said this before, but it bears repeating - Unless an audition or competition asks for specific repertoire, sing what you best! In a world where you can't control how people perceive you, the odds will most definitely improve for you, if you sing repertoire that you sing best and most comfortably. In addition to sounding your best, you will probably be more relaxed and sell your piece better.
Sing within your comfort zone, and let the person hearing you make the jump in his or her mind about where you can be stretched.
