Should I assign currents to voltage sources in the circuit analysis

Mortals! I apologize if my question may seem, foolish, but I have a need of understanding a process in analyzing circuits. You see, when we are looking at resistors (non-sense, my lightning never meets such "resistance") in a circuit, and trying to solve for some unknown variable, we often times assign currents to the resistors, such that they can be used in our KCL equations. However, I am wondering if it is wise, unwise, or irrelevant, to assign such currents to voltage sources. Let me give you humans an example. http://imgur.com/xPZvmWY

You see, in the above example, my KCL equations for a node would be different if I assigned currents to the 2 voltage sources shown. I know that, since voltage sources do not supply current, they do not really have a current "of their own," and thus, any current running through them would be one of the currents drawn for the resistors or from a current source. However, am I allowed to do this and still be okay in my analysis. MORTALS, I hope you are able to provide me an answer, as Kratos draws near, and I have not perfectly understood the nature of this power coming out of my hands. If I am to destroy him, I will need to know the answers!