I like frosted warm white LEDs in classic games. For the backbox, I try to use something that is not as birght as a 2 SMD, but for the playfield and inserts, 2SMDs are the way to go.
For backbox, I like the 1 SMD warm whites or the 2 LED warm whites (about the same brightness). Too bright, with a clear dome, and you'll get spotting.