this year i bought my dad a ton of cds (boring for some, but perfect for him!) and a GPS for my father-in-law, who is really into older cars and taking long drives.
i think the GPS is a great gift, if he doesn't already have one in the car.
a past co-worker of mine bought her dad a remote car-starter one year, which, if he lives in a cold climate, is a great idea imo!