We've talked about traditional publishing and self publishing. Now we're onto the third option for writers these days: small press publishers. They're, by nature of their name, smaller than the NY based publishers. They're spread out all over the world. And they don't require an agent to get into.
Now, one of the benefits that small presses have over their larger counterparts is the size of the slush piles. There are fewer authors to compete with so it's more likely your book is going to get read. Chances are if they like your book well enough, they'll give you a shot.
Small press publishers are also more likely to take on a new author. It's hard to break into the business if you're just starting out. The publishing giants might have a hard time noticing you if your work isn't best seller class material. But a small press will take on new writers, so long as they write what the publisher is looking for and it's a good quality piece.
If you're writing in a niche that isn't very well supported by the bigger publishers, you're going to find it hard to sell your book to them. They don't want to take the risk. But the small press publishers are more willing to take a chance on you. You may not write in an easily definable genre, or you might be opening up a new niche for yourself. Chances are, again if you're writing quality work, someone will choose to give you a chance and publish it within the small presses.
The larger publishing companies tend to overlook what an author wants to go with what they think sells. This may or may not be something the author wants to do. With small presses, you maintain more control over your work. This sometimes includes the type of cover art, how your blurb is presented, if you want to do just print copies or e-books or both. As an author with a small press you have many more choices. More often than not, if you do print copies, you'll be working with a POD service like CreateSpace. This saves on overhead and the cost of a warehouse.
Again, small publishing may not be what you're looking for. As always, do the research. Decide what you want to do. If you want to try your hand at multiple things, go for it. There's always something to learn.