I find that heavy dumbbell shrugs are a good basic exercise for traps.
I also find though that adding a very heavy set or two of shrugs following my deadlift routine is a good shock to the old traps.
If you have a Hammer deadlift station in your gym, try a few extra heavy sets of shrugs with this machine, provided you're well warmed up. You'll feel it the next day!
I tend to think overall that the people who have the best traps are those who don't neglect them. You don't need to find the perfect exercise, just train them heavy and don't leave them out of your routine for weeks at a time and you'll be fine.