I'm clearly biased towards going with the trade/traditional publishers, but that's for a number of very good reasons:
Everything Cameron just said. I've been at this indie publishing thing for almost 6 years now (I've now done four books indie) and I can say his points about the advantages of traditional press are entirely accurate. I know a number of fellow authors who have gone traditional, and the baseline you start with in traditional press is just so much higher than indie. There's nothing *wrong* with indie, but turning down traditional press in favor of indie (when you're starting out) is simply not what I'd recommend.
I feel like my latest book is the best book I've written yet. Advance readers, reviewers, and even the editors and agents who rejected it all seemed to agree. Yet despite the positive press, it's hardly sold anything, and that's because no one has heard of it. There's just SO MANY indie books (and authors) out there that's it's extremely difficult to stand out from the pack. Every so often an indie author blows up, but the conditions are random (kind of like landing an agent, honestly) and this is like 1% of the total indie author group. As authors, we tend to have a rather overly optimistic perspective on how much we'll sell.
Traditional press gets you, as Cameron said, a built-in audience, and from talking to agents, editors, and fellow (traditional press) authors at conventions, I've pretty much consistently learned that even a poorly selling traditional press book still sells more copies than even well known indie books. I like to think of book publishing through the metaphor of a mountain - every author wants to get to the top of the mountain (where people like King, Scalzi, et all hang out) and most never make it. However, indie authors start at the very bottom of the mountain, and they have to claw and climb the entire way up. Traditional press authors still have to climb that mountain (and also might not make it to the top) but they start at a base camp a good way's up the slope.
Finally, the fact that indie publishing is available means striking out in traditional press (not earning out, essentially, and not getting another book deal) *still* leaves you the option to go indie after traditional, and authors who have gone traditional first usually obtain at least a small audience and some cred. By going traditional press you have made contacts and likely acquired an audience (and a starting point) far beyond that of the average indie author. Again, having done four books on my own (and seen the expected lack of sales/exposure, despite advertising and connections) there's always the chance something I do indie will take off ... but I'm not holding my breath.
Landing a book in traditional press, taking advantage of the signal booster/accelerator that results, and then either succeeding (if it goes well) or going back to indie (with some new momentum) are both far superior to going indie out of the gate (IMO). I'd never recommend going indie FIRST. Once your debut book has struck out everywhere, if you've got great feedback, absolutely go indie - but why turn down the chance to go traditional (and take advantage of all the things Cameron has pointed out) without even trying?