Oscilloscope - since you mentioned no bandwidths needed or frequency requirements. Rigol DS1054Z is one of the best budget scopes. Since you are working on high power electronics you likely will need a high quality differential probe. Expect to pay just as much if not more for the differential probe than you did for the scope.
Precision Power Supply - How precise? That's like saying you want a fast car (this could mean a tricked-out civic, a pony car, a porche or an F1). Many on here love the old used HP 6114A and 6115A series or the Power Designs Precision models. Very tight tolerances, low ripple and with the HP you can combine more than one of them in a variety of ways. You will pay way more for new (easily 10x-50x more).
Precision Multimeter - Once again, we need specs. Words like precision are relative.