1. Plains are one of, if not the most common biome. Flat, with lost of tall grass, decent biome.
2. Forests is a biome full or oak and birch trees. it is also one of the smallest.
3. Jungles are arguably the most hated biome. Containing huge jungle trees and shrubs. Jungle temples spawn here, I perfer these over Desert Temples.
4. Desert are very barren biomes. Containing cactus and sand stone. Desert temples spawn here.
5. Ocean is almost empty biome. Containing almost endless water. It also has the occasional island and mushroom island.
6. Swamp biomes are always next to an ocean biome. Containing witch huts and mushrooms. Very nice biome, in my opinion. Also number 4 of the rarest.
7. Extreme Hills are the 3rd rarest biome in Minecraft. Containing huge mountains, rich mines, and beautiful landscape, one of my favorite biomes.
8. Tundra or Ice Plains biomes are the second rarest biome in Minecraft. Containing snow, Frozen Oceans, Ice Mountains and the occasional oak tree.
9. Mushroom Islands are by far, one of the rarest biomes in Minecraft. Containing no trees, Mountains, mycelium instead of grass and the rarest mob in the game, mooshrooms.
– Source: http://www.minecraftwiki.net/wiki/Biome