If you happen to be in Seattle for New Year's Eve, you're in for a really good time.
The city of Seattle presents a fireworks display at the Space Needle. From all over the Seattle area you can see the fireworks exploding around the Space Needle beginning at midnight. It's a wonderful sight!
The downtown area does get very crowded for the fireworks. If you're driving, get there earlier in the day so you can find a spot on the street.