If you can't hit the notes I'd say:
Make your limitations your strength. Use your voice in strange ways, write some good lyrics, use some effects if you like. Listen to a lot of great records with tecnically poor singers who makes their lack of Tim Buckley-factor a fascinating element in their music. The list could be long, a few examples is The Fall, The Velvet Underground, Bob Dylan, Pavement, Leonard Cohen, early Nick Cave/The Birthday Party.
Or work really hard to improve your tecnique and your ears.
I dread a future of people who sing with robot-like perfection because of... robot like perfection generated by a machine. If you got interesting ideas, listen to great music and work really hard then you'll probably make it somewhere. Autotune won't do it for you.
Just my opinion of course.