No one source is going to give you everything you need and quite a few are pushing an agenda or trying to sell you something.
Most people stack for several reasons and their stacks reflect this,
I have junk silver in case of a meltdown (or as something to sell to people who think there is going to be a meltdown).
I have old world coins for my collection and because I am trying to put a treasure chest together full of coins you can actually touch.
I have .999 silver coins because they can be collectible and if silver doesn't go up then the coins will appreciate in value as people look to complete their collections.
I have silver bars because silver is silver and if it goes to the moon then I want to be able to sell silver without worrying about the pretty coins melting.
I have gold because despite silver having the most upside potential in my opinion, the banks tend to disagree and they are buying up gold. They know more about this sort of thing than I do and I figure if they are getting gold, I should too.
Predicting prices is pretty much impossible.
Learning lots is a good idea though, an afternoon following links on Youtube will help if you promise not to believe everything they say. These forums generally post up links worth a read, the DailyReckoning will send you a free email about world economics everyday and they are very keen on gold and also silver. There are a few books but I have never read them, there is plenty of information freely available on the internet. "Money as Debt"
http://www.youtube.com/watch?v=rC720Cl3N-0
is a good place to start as an overview as to how we got into this situation, I had to watch it a couple of times before the penny dropped but I am a bit slow when it comes to cons on such a massive scale.