Faced with the same decision, I figured that a PJ or TV now might be the reverse in 5 years. Here is what I did (and it's NOT much more money but MUCH easier to do before the walls are closed up)

1) Determined the viewing wall and added a 20 amp circuit for the equipment and put two more 15 amp boxes on either side of the 20 amp (the 20 and each of the 2 15s were separate circuits}

2) buried some pipe in the wall to run cables/wires. Figured what I needed for speakers/HDMI/Component and ran that before drywall wnet up

3) Ran CAT6 for a network connection

4) Added a couple of extra studs to hold up to a 65" plasma TV

5) ran 14ga. speaker wire to the sides and behind the viewing area for 5.1 / 7.1.

6) Put an outlet in the ceiling for a PJ. Also ran component and HDMI from the PJ down the aforementioned pipe.

monoprice keeps the expense way down for cables.

Anyhow, the more you can do now, the better you will be later.