Headlights

Yup. Or you can do a text heavy version of H4s on my website (which will link back to Dan's website) Short version is this.
Sealed halogens will be an upgrade over plain sealed beams.
H4 (or the DOT approved varient) will be a big upgrade in beam pattern and light quality.
All use the same wattage. The H4 is a bit more sensitive to voltage drops (you'll see the lights dim a bit if the alternator isn't keeping 14 volts at idle).

A big problem with all A-bodies I've owned has been the headlight wiring is the absolute minimum that current needs. If everything is in tip top shape, you're oK. If not, you'll get to find the weak link. In my cases, its been the circuit breaker in the headlight switch, the connector to the back of the switch, ground wires on the headlights themselves (chafed on the bucket). The best solution on a non-concours restoration is to install relays. The headlight switch then powers the relay (very low current draw). The relay when powered then switches on the headlights. The high draw power can come right off the alternator to the relay and then to the headlight. As these new wires are not on the main fuse or circuit breaker, adding a fuses is a part of the upgrade.

PS> Scott Harvey discovered that with H4s, foglights were no longer needed and he could use the auxilery lights on his rally cars for cornering and long distance lights.