New House, Old Wire

If you insist on grounded outlets, I'd recommend wiring only the plugs you intend to use for your stereo (one two-plug box should do it in an apartment). Doing so will reduce the cost, and keep relations positive with your landlord.

If there is not a ground in the outlet box, you can not install a 3 prong grounded outlet. This would be the case if knob and tube or romex without a ground wire is the wiring method. You could replace the two prong outlet with a three prong GFCI outlet but the sticker that says "no equipment ground" included with the GFCI must be put on the cover plate. If metal clad cable is used "BX" and it goes into a metal outlet box with the correct clamps to secure the BX to the metal box, you could connect a ground wire from the box to the outlet using an approved ground screw.

Jon:
You didn't say what year your place was built but if it's old,it may not be as simple as new outlets. A lot of SF apartments have house wiring left over from the days when electricity was new to residences. Some of it was DC. A lot is "Knob and Tube", the days before romex. And certainly no one had 1500 watt hairdryers. That's why some rooms have one oulet and some none. No need! Grounded AC may have come along after that apartment was built.(In fact, if your place is really old you could have a live, capped gas line to where what used to be room lighting in your ceiling) Electrical service to that apartment may not be able to handle much. A grounding wire may be needed but that could be just the tip of the iceberg. And be certain that if your outlets have two wires only, no one took the time to check phase!! The good news: If you're renting a place built prior to 1979 you have rent control!