Does Spokane get that cold and wet? (I used to live in Seattle and while I made it over to Wenatchee & Ephrata a lot, it was in spring/summer/fall, not winter. I assume Seattle is usually much warmer than Spokane.). I usually use leg warmers down to upper-mid 30s, and windproof tights below that. My legs are generating enough heat that wet hasn't been a problem, as long as I keep core, head, and extremities warm. So waterproof gloves and shoe covers or waterproof socks (Sealskinz) have been more important - the gloves in particluar. I scrounged newspaper or kept a spare set at work in case they didn't dry out from the morning's ride. I do have rain pants (REI, watch for a return/outlet sale) but use them more as a wind-blocking layer when it's mid 20s or below. This was for a nominal 20 minute/5 mile commute through last winter. Current ride is 40-50 min with stop lights, and I discovered last March I needed less insulated clothes because I became warmed up faster and better on the longer ride.

edit - looks like 2 votes for the REI pants! They have a very long zipper, which makes it easier to get the on/off without removing cycling shoes.

I've had good results for base layers at Target, their Champion line is a reasonable knock-off of more expensive name brands. There may be something sold to runners that would work well enough on a bike.