We've got pages and pages of detail on our bulbs and how to become a lighting expert, but if you want one bulb to rule them all, the answer is: frosted 2SMD bulbs. See them in use below in the backbox of Judge Dredd. Mostly whites, but with a few strategically placed colors.
The bulbs that turn on and off to indicate game status & features often need a special type of bulb to prevent flickering. For those, we recommend: frosted 1SMD non-ghosting bulbs. Most people choose to color match (red bulbs in a red insert, green in green, etc). Again, you'll need to know if you need wedge or bayonet.
LED Flashers for modern games
Modern games have larger bulbs that flash quickly and brightly. These bulbs have larger sockets, and those sockets are at a higher voltage. Usually you will find these under colored domes above the playfield (often along ramps), or under large inserts under the playfield. Our 8SMD flasher bulbs are the most popular by far, but they are very bright, so some people will opt for the dimmer 5SMDs.