I personally think that the situational awareness that TrackIR provides is most important. Also, it frees up 4 buttons for views from any joystick. So, I would go with TrackIR and a cheap joystick if that was all that I could afford for now. And get a good stick later.
That said, there are may awesome pilots who still don't use TrackIR, and use the hat on their stick. So, it's a personal decision. But I love my TrackIR!