bittering hops

[Cadbury]

G'day men,
How much flavour comes from hops used for bittering(boiled for 60 minutes) I have read that the actual flavour is lost and only the bitterness comes through. If this is the case, then why do we use different types of hops for bittering? Why not use the cheapest? John Palmer, in his book, said to save the more expensive hops for flavouring not bittering. Is he hinting at the same thing? Can anyone shed some light on this subject?
Many thanks,
Cadbury

[Tipsy]

In lighter style beers I can taste the bittering hops and I usually use a noble hop for bittering unless I'm after a specific flavour.

In heavier malty beers I use whatever is at hand for bittering.