When you say "the upcoming YC round", do you mean 4/02/08? If so, I imagine that you'd be better off applying as a single founder. Probably not a good idea to go into business with someone you've only known for 8 days. As a single founder myself, I'd need at least 6 months to a year to get to know someone and work with them before I'd make a commitment. Better yet, I'd prefer someone I've known for years, but the dozen or so possibilities always seem to have some other road block.
Is there anyone you already know and have worked with before that could join you? That way, your odds would be much better (for YC and beyond).
Good luck and keep us posted.