I cross county, so breathability is very important
For base layer, I used to use lots of Sporthill stuff but have switched to Smartwool because it breathes so well, no stink, warm when wet, wears like iron. I also use a Smartwool sweater for warmer days- breathes a little too well if it is windy!
I still like my Sporthill beanie- warm enough, breathes decently
The Sporthill XC pant is still my mainstay (only!) pants. The 3SP fabric is warm enough down to the low 20's with no long johns, breathes well, is windproof to 30 mph, wears well.
On cold days a smartwool base layer, smartwool sweater and a breathable shell work well. If its really cold a Sporthill 3SP jacket.
Socks- my feet get cold easily so smartwool socks, then LL bean fleece socks. Lately- also wearing overboots even when it is pretty warm. (these ones fit NNN boots; http://finnsisu.com/store/yoko-yob-2-fleece-overboot.html )
I have some older ones for 3 pin boots (boot glove), but I don't think they are still made.