There are some people who will always want to go the traditional route. There are some people who will plunge straight into self-publishing. Often, both these groups can be disparaging or dismissive about the other choice of direction.
I think the polarisation is unfortunate and not particularly helpful. Every writer will make choices dependent on their personality, their opportunities, their wallet, the free time available to them. What suits me may not suit you - and if we were all the same, what a boring world it would be.
I think each writer should instead ask themselves what really matters to them...
Prestige or validation:
You need a traditional publisher, preferably one of the Big 6. This may change in the future, but right now it's true. Having said that, your friends and family probably won't know any different, but you will in your heart and this is about what matters to you not them.
If you go into writing with the sole aim of making money then you are deluding yourself. There is a very small percentage of writers who make more than the national average wage, but writing is not the route to riches unless you are incredibly lucky. JK Rowling and Joe Konrath are exceptions, not the rule.
There are some self-publishers who are making serious money, easily as much as they would from going the traditional route. However, they are not in the majority and most self publishers consider themselves successful if they earn more than a few thousand. A traditional publishing deal will almost certainly be for more than a few thousand, and an agent should be able to sell other rights. But until you get a deal you're going to get nothing...
Getting the book 'out there':
Self-publishing without a doubt. You can be up and running via Kindle or Smashwords in a very short time. Print on demand (eg Lulu.com) means you can hold your book in your hot little mitts even if it's the only copy that ever gets printed.
Again, self-publishing is the way. You have very little control in the traditional route. This way you get to choose the design, how it's marketed and promoted, what price it sells at - everything is up to you. You get none of this with the traditional route.
Self publishing means you have to do a lot of stuff in front of a computer screen that isn't about writing your book and, in the tradition of 'you don't get something for nothing', you have to do a lot more than you originally bargained for. Editing. Cover design. Typesetting. Book design. Admin. This leaves less time for writing.
With the traditional route all the technical and production aspects are taken care of, and a lot of the promotion (though writers are expected to do a lot of promotion themselves).
Personally I know that I'd quite like to have a go at e-publishing one book maybe, but I don't have the interest/patience to do much more than that. I certainly don't want to run a small publishing business. But that's my choice. No reason why it should be yours.
PS Sorry this is late - I completely forgot. Oops.