One of the key messages from Keith Anderson was the value of tempo runs. He said that intervals and other speed work was all very well but it did not build up speed endurance in the way of tempo runs. At his prime he was running for 60 minutes at his lactate threshold and put his success down to these sessions.
The soft-core runner in me was internally saying yes but no but yes. That sounds hard.
Afterwards I was talking with Joe Beer and he was saying that you actually don't need to do too many hard sessions. Research with successful athletes showed that they did a surprisingly high proportion of their mileage at an easy pace. If you think of an 80:20 distribution and you do 30 miles a week then you should only by doing 6 miles hard (and even that was not strictly necessary - certainly not at my standard).
So yes threshold work will do me good but it is probably more important to get in a good base.