In responce to fonchick, I have used position in queue to great effect. You DO have to be careful what type of queue you use it on but if used correctly it works well.
In our situation, we have a specialised Tech Support queue and I have increased time before abandon from around 5 mins to 8 mins. I know that this sounds like an awful service, but it is highly specialised and calls can last at times over twenty minutes. This service is only charged at national rate, not premium, so people are more willing to hold.
PD-S