The number (singular or plural) of an [noun] adjective used with a collection word

Hi, I have a simple question that maybe have a not so simple answer, but I hope that it does.

In English, we can use noun as adjective. Therefore in that context, the noun should follow the grammatical rule of an adjective.

So in the plural form, I would expect it to be singular:
http://en.wikipedia.org/wiki/English_plural#Nouns_used_attributively

There are also word tha represent a collection of things, such as "collection", "list", "group", etc.

I have an hard-time deciding what is the best number (singular or plural) rule for a noun-adjective used with a collection word. There is maybe a rule or maybe it is a grey area where people maybe define their own rule. So what it is?

So with practical examples:
- "Member list" or "Members List"?
- I guess we say: "List of Members"

If I take the wikipedia reference I gave, then I should say "member list".

It is very clear when we say, this is a "beautiful list/collection/group", since this qualify the list/collection/group.

However, when we say "[word description type] list/collection/group", it is harder.

- "Price list" seem way more used than "Prices list" (my assumption is based on existing google result)
- But we will say "List of prices", right?

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- "Stamp collection" / "Card collection" seems way more used than "Stamps collection" / "Cards collection" (my assumption is based on existing google result)
- "Collection of stamps" seems more used than "Collection of stamp" (my assumption is based on existing google result)

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Of course, in wikipedia they list exception when a word cannot be used in a singular form, like "glasses" (they call this pluralia tantum), e.g., "glasses" case.

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I am repeating myself there, and I am mostly looking for confirmation that my understanding is right. My conclusion so far are like my example:
- [singular noun-adjective] + list
- list of [plural noun]

What do you think? Or rather, what is right? ;-)