What I don't understand (well, I do sort of) is that you give out your mobile phone number at every available opportunity during the buying process, yet none of the buggers ever bother using it.
It would be so nice if you could rely only on having your mobile with you at all times to be sure to not miss a delivery. Yes the ringing ahead of time is good, but if they get no answer from the doorbell, they should buzz your phone and see what's going on.
Then you could be in the bath, shower, still asleep, whatever, and still not miss the delivery. It would also save the delivery firm money as they wouldn't have to re-visit. I suspect getting the drivers to do this is a step too far, however.
You should also be able to track your parcel in eral time online via GPS. That would be cool. I guess there are security issues with this though.