Tahoe is fun for the partying. Personal preference, I'ld way rather spend my time in Mammoth.
By west, how far west are you talking, cause we usually refer to Colorado as going East, Cause well, there isn't much East of CO to talk about.
Solitude in Utah is fantastic and way less crowded than I thought it would be. Big Sky is amazing if you don't mind being cold, possibly being in an avalanche, and fresh powder pretty much every day. I've never had more fun skiing trees than in Copper. Big Mountain offers a great bang for the buck.
I want winter now.