For ribs, I like to get them trimmed and rubbed about 10 hours before cooking. I don't like the rub to sit on too long, as I use alot of salt based rubs and it seems it gets harder to get moisture back in the ribs if I let them sit for an extended period of time.
They way I cook ribs, either baby back or St. Louis style, is run a mix of oak, hickory, and apple smoke through them for 2 hours, foil with butter, honey, and my sauce I make for 45 minutes, then smoke another hour to hour and a 1/2 un-foiled, and mop them the last 30-45 minutes of the cook. I like my ribs firm, but not chewy or have to pull the meat off. Just a nice easy bite, and it's done perfect.