I don't think it's vanity to want the endorsement of an agent and publisher. Self-publishing (as distinct from vanity publishing) is perfectly respectable but for many the waters remain a bit muddy. It is very easy to get a shoddy product out there. At least if you publish via the traditional route and then say "I'm a published author" nobody can look down their nose and mutter under their breath "Yes, by your good self." I can see the benefits of self-publishing, and may even do it one day, but I'm afraid I am still very heavily in favour of traditional publishing if I can only get a deal. At least for a debut.