Spawn at the border of two cold biomes with an igloo nearby (282 65 136). Unfortunately, there is no secret underground room here, but it can serve as an excellent shelter nonetheless.
You should be able to find a spider spawner at these coordinates 325 25 430 that is adjacent to a huge mineshaft. The chests inside the spawner contain:
Also, take a walk around cold taiga and you will probably catch a glimpse of polar bears - a new type of mob in Minecraft 1.10.