My main source of income is also my day job. It is a part time job that I hold mainly for health benefits.
I get the other half of my income from writing and auctions. I would like to become 100% self employed and earn all of my money from writing.
The thing to keep in mind is that you will not earn all of your income from hubpages. You need to write a lot and sell your writing everywhere that you can. Or sell something else and use your writing to boost those sales.
I currently write fiction, non fiction and web content. I am working on a novel. I sell my web content to buyers I find on eLance and Constant Content and I am always looking for other places to hawk my wares.