Mostly I would point to the responses in this thread
. Especially be sure to check what to expect on the Pick-a-Brick wall
On army builders, I was at the store west of Philadelphia a couple of weeks ago, and I saw some of this torso in the 'build-a-fig' station:
Generally speaking I see more town fig parts in those, but I don't know if anyone's ever done any sort of quantitative analysis of what shows up in those. Occasionally I see something old, which I snatch up if I see it, e.g. relatively recently I got the torso and tailfin for the Harry potter Mermaid.
Otherwise they tend to be fairly recent things. If you do see a lot of good army builder torsos, you should ask them if you can just get any fifteen parts rather than having to include three legs, three torsos, three heads, three hats, and three accessories (this was mentioned as a possibility in that other thread, but someone also mentioned that they would be changing the policy).
Also, at least at the store I went to, they are currently carrying this issue
It's very train centered. A few other articles, but almost all train stuff. It looks like the next issue
of BrickJournal (which won't ship until later in the month) will be castle focused, so that's something to keep your eyes out for.