It is also worth mentioning that Techstars, besides 500 startups, is also a good program. Don't kid yourself though: they are all as picky (if not more) as YC. And as rmorrison said[1]: If you think you need YC to succeed, then you won't (and shouldn't) be accepted
[1]http://blog.rmorrison.org/advice-for-yc-applicants-on-the-fe...