My list:
1-clean or power cleans--any olympic lift
2. dumbell or kettlebell snatches
3. deadlifts-snatch grip deads are best, IMO
4. any type of chest supported row
5. seated cable pulls to neck/face (face pulls)
These are the movements that I contribute to most of my trap development (my upper back is probably only second to my legs as far as best bodypart).
I only do conventional deadlifts twice a month on my dynamic effort lower days. On these days I use 60-70% of my 1RM and do 8-10 sets of singles. Sometimes on my lower body days, I'll use snatch grip RDL or snatch grip DL's for 3-4 sets of 5-6 reps and those kill my upper back/traps.
Chest supported rows and cleans seem to really hit the lower traps and add thickness to them. Any clean or snatch really works them well. I can always count on getting a good pump and DOMS by doing a few sets of face pulls, though, and they also hit the rear delts and prevent shoulder overuse injuries pretty well.
My 2 cents.