I've mentioned before that it really bothers me when authors have the mentality that they can't make it without a publisher. Now, often that is a result of habit, but you also see the "I need a publisher" mentality coming from brand-new writers.
In that case, I understand it more. There's a term self-published authors (especially those who are refugees from traditional publishing) use to describe the appeal of having a publisher: Validation. Typically that's said with a sneer ("He's just seeking validation; he doesn't care if he gets ripped off."), but with new writers, validation is something that is actually needed. Until you've gained enough experience to trust your own judgment, having someone say, "Yes, this is good. You aren't a self-deluded fool. You can write," is very important.
Validation doesn't need to come from a publisher, though. I had memorable validation experiences in journalism school as well as on the job, and ironically enough, throughout the whole agent/traditional publishing merry-go-round.
The ones that meant the most to me were the ones that came from my journalism professors, not the ones that came from my professional colleagues (no matter how much I respected them). That's because editors edit things to the standards of acceptability for that particular publication, not to the abstract standard of goodness the professors were interested in. The analogy I used to use was that we were making Big Macs: When you're making Big Macs, you certainly want to meet a certain standard of professionalism (two patties, three buns, no spit), but you also need a consistent product (two patties, three buns, don't get creative) and you need it finished at a particular time (meet your deadline).
The problem is that, like most cooks, most writers don't want to make Big Macs. They don't want to be Queen of the Big Macs. They know that making a Big Mac isn't very hard, and it isn't very interesting, and it's hardly an expression of their unique individuality.
So once you get a peek behind the curtain and realize that the validation from your editor is coming in the form of, "You sure made a good Big Mac!" that validation isn't actually all that gratifying. That's why more-experienced writers feel like they don't need it--they know what that kind of validation means. A reader telling you that they loved your book and can't wait for the next one to come out means more. That kind of validation means that your crazy experiments with Thai/Italian/West African fusion cuisine actually paid off.
Another reason new writers give for wanting a publisher is that they view it as their education. Instead of paying for classes or to hire people, they give up a potentially enormous hunk of future earnings to pay for the experience of getting published. That experience is supposed to teach them the ropes.
The problem I have with that is that I've worked with writers, and guess what? They weren't privy to much. They would turn something in, and then they would vanish--I never met any of the writers I edited, and I rarely communicated with them. They were kept out of the office, and they certainly never communicated with anyone in production (which I did, a lot, and yet I still didn't know everything about getting a book out). I freelanced as a writer on and off for a decade with one company, and I never met anyone from that company. Not once. I may have gone to their office once to drop something off (in which case I may have met the receptionist), but I'm not sure.
When you're a publisher, educating writers is not your goal. Getting an acceptable product out on time is the goal. Having a bunch of writers sniffing around the office getting in the way so that they can get an education (which benefits the publisher how, exactly?) does not help you get your product out on time.
Now, all this assumes that your publisher knows what makes an acceptable Big Mac. Not all publishers do. Have a look at this post (via PV): People actually sign with publishers who make their work look terrible and don't distribute it outside their own Web site.
And while you're pondering whether to sign with a publisher, here are some more questions to think about: How is your publisher coping with the changes happening nowadays? How are they handling e-books?
And who do they work with? You may have noticed a lot of fighting going on among the various e-book retail sites: If you want to stay neutral and have your stuff available everywhere, but your publisher uses IPG as a distributor, that's just too goddamn bad for you. And let's hope the people running your publishing house successfuly navigate these very dramatic industry changes, because if they don't, you are completely screwed.
PV's version of that article has some pointers for finding decent publishers, but the fundamental problem with any publishing contract is that it sews up the rights to your book for a very long time. If you are looking at the world of publishing today and going, "Oh my God! I can't tell what's going on! I don't know what's going to happen! It's so crazy!" realize that the exact same thing is true for the publishing houses--big, small, new, old, whatever. They are all looking at the future and peeing their pants, which is why some of them have done some really stupid things and are in legal trouble now. There is no one out there who knows what's going to happen; there is no one out there who knows who the winners and the losers will be. All you have is your book--do you really want to give that up?
And if you're wondering whether something as arcane as your publisher using IPG as a distributor could hurt you, I present you Ted McClelland, who was getting half his income from Kindle sales before IPG fell out with Amazon. Utterly screwed, and utterly powerless to do anything about it.