hi, very welcome addition imo. I know this is not place for feature requests, however if your working in this menu area, "snap selected to center" seems missing here.

The reason I implemented Snap Selection to Active is because I found myself frequently doing Snap Cursor to Selection then selecting a bunch of other stuff and doing Snap Selection to Cursor. I don't think snapping stuff to the center is really that common (most of the time Alt-G will suffice). That said, if it would be helpful, then I'd be more than happy to implement it :)

@Isaac Weaver (wisaac) yes Alt/g does the object, but not the cursor, making it 2 moves to "clear object location & snap cursor to selected" There's times where this is very handy, similar to your addition, I find doing the 2 moves happens regularly with snapping both the cursor & selected object needed in object creation & modeling.
Thanks.

@Brendon Murphy (meta-androcto) You're saying it would snap the objects and the cursor to the center? I can see how that could be useful, but it seems like a bit of a corner case. Either way I would like to get some more input form people before implementing it, maybe you could open a feature requrest on rightclickselect.com?

@Isaac Weaver (wisaac), hi, yes, it's "You're saying it would snap the objects and the cursor to the center".
Place the cursor anywhere in the screen, shift/a a new object & it's created at the cursor location, which may or may not be the desired outcome.
Append an object from another file & it's created at the original location which may or may not be the desired outcome.
Having a way to reset the object & cursor at 0,0,0 in one move seems time saving in these & possibly more cases.
I'm not fussed with this enough to do a entry on rightclickselect.com, If you think it's good, go for it, if not, stick to your original patch, I can always add to the spacebar menu addon as there's already extended snapping methods available there.
Cheers :)

@Brendon Murphy (meta-androcto) I'm probably not going to implement it the C code, but I did write a simple python script that should work just as well:

import bpy


class SnapCursSelToCenter(bpy.types.Operator):
    """Snap 3D cursor and selected objects to the center"""
    bl_idname = "view3d.snap_cursor_selected_to_center"
    bl_label = "Snap Cursor & Selection to Center"

    @classmethod
    def poll(cls, context):
        # Only works on objects
        return (context.mode == "OBJECT")

    def execute(self, context):
        context.space_data.cursor_location = (0, 0, 0)
        for obj in context.selected_objects:
            obj.location = (0, 0, 0)
        return {'FINISHED'}


# Add the operator to the snap menu
def draw(self, context):
    self.layout.operator(SnapCursSelToCenter.bl_idname, text="Snap Cursor & Selection to Center")


def register():
    bpy.utils.register_module(__name__)
    bpy.types.VIEW3D_MT_snap.append(draw)


def unregister():
    bpy.utils.unregister_module(__name__)
    bpy.types.VIEW3D_MT_snap.remove(draw)


if __name__ == "__main__":
    register()

This will add an option to the bottom of the snap menu called "Snap Cursor & Selection to Center" which will move the selected objects and the cursor to 0, 0, 0

Hope this helps!