Matt - Welcome aboard!
I have used the Hartford Products trucks and they are quite good as well. Hartford makes a good bit of SP stuff, detail parts and such. As Bruce said they are white metal, but very good detail.
Bachmann makes some good products, despite what might be said. I use their Spectrum couplers and have had very good luck with them. Their wheel sets are as inexpensive as you can find, and many here use them. They currently list three wheel diameters - 24.5mm, 31mm and 32.5mm, so you have some flexibility. There are other manufacturers of wheel sets as well, Gary Raymond and Sierra Valley and others. USA Trains makes an arch bar truck (less wheel sets) that re inexpensive and work well.
As for construction materials, I use whatever leftover lumber I have from projects around the house. Mostly it is ‘white pine’, with some oak or other ‘hard wood’ thrown in for whatever reason. I use Gorilla glue, Tite Bond and Elmers Carpenters glue (the yellow stuff). Paints are Krylon/Rustoleum or regular house type paint, depending on what the project is.
If you can’t tell, I am far from a rivet counter. Somewhere on this site is a build log on some D&RGW 6000 series flat cars I need to finish, but it will give you a good idea of my modeling style. Hope this has been of some help.
I was not able to find the links to Bob Sorenson’s excellent threads on cutting scale lumber on both a table saw and band saw on the My Large Scale forums, but I have posted a copy of the threads on my web site here:
http://www.gscalejunkie.com/Articles/MillingScaleLumberRev-01.pdf
I created this PDF for my own use, but now see it might be a great resource for everyone.
Bob C.