You should not need to realign them solely based on changing the bulbs, but it never hurts to check the alignment.
Seating the bulbs properly can be a PITA due to lack of room for your hands, take your time and be sure they are seated properly. If they aren't, you will find the alignment WAY off.
I replaced mine several years ago with PIAA Extreme White Plus headlights and Philips 893 CrystalVision driving lights. They aren't HID's by any means, but a nice upgrade over stock and all I need given the limited night driving I do.