Ask HN: Need career advice on software field to specialize on

I'm a software developer with about two years of experience, working for one of the big four. I recently joined a team that does some really cool stuffs, but it also made me realize my dispassion for maintaining services and the on-call responsibilities associated with it. These days I'm feeling a bit down by the fact that virtually all the software jobs out there will have such on-call responsibilities.

I also feel like my career has no real direction right now, and I wish to specialize in some technical field or business domain. The things that are important to me are:

1. Work-life balance: I would like to work in a field where my only responsibility is at work, 9-to-5. 2. Money: I like the amount I'm making at my current place at would like to at least maintain my salary. 3. Depth of domain field: I find that I'm more cheerful on days where I actively learn things and not so cheerful on others.