I've had problems over the years with every tricep exercise, but in the end I think the exercises I really like are
1. Close grip bench press
2. Cable pushdown (all variations, especially the one 1 and groink posted).
3. Dips
If I do skull crushers, I'll do them off the floor these days. Easier on the elbows. I also like the seated overhead extensions with a dumbbell, but those can be touchy (again, elbows).