In Game
In game you face Snow Elves as the Falmer who are very good warriors, spellcasters and archers. They sometimes have 'pet' Chaurus or Frostbite Spider, they usually poison their weapons so before facing them have some poison resistant equipment or some cure poison potions. Falmer are blind so light spells and torches won't alert them but their hearing is very acute so using a muffle spell or having muffle enchanted equipment makes you basically invisible to them.
With the Dawnguard expansion you meet Knight-Paladin Gelebor one of 2 remaining Snow Elves.
 Weapons and Armour
Falmer weapons and armour are made from Chaurus Chitin and are very strong, early game. You can loot an entire set behind a locked door in Mzinchaleft and also in the Dawnguard expansion there is Ancient Falmer Armour. You can improve Falmer Armour using Charus Chitin.
You are not able to play as a Snow Elf in the game even with Dawnguard installed.