I suggest that you have a look at Mark Verber's site.

I guess the other thing is to build your clothing set incrementally; go on a hike, see what others have, what you wish you had brought instead, fill in that hole. Of the items you mention, the long underwear might be useful for sleeping, but I personally can't wear longjohns on any but the coldest days; your metabolism (and pace) might be different.

I do suggest you consider some sort of long sleeved hiking shirt, all-synthetic (not a cotton blend) from REI or the like (careful, even at REI some long sleeved button-up shirts are a cotton blend).

Pacific NW: I live there too, WA state. If in the Puget Sound area, consider going on some backpacking trips with the Mountaineers. If in the Portland area, the Mazamas. In general, just see what others are wearing/carrying, ask how they like what they have and why.