Ah, opinion lists. Time to add mine
1. Earth. Deadly fast, and inexpensive to boot. This is more or less the speed deck that other decks WANT to be.
2. Aether. It may not be as fast as other decks, but it's idiotproof. Invincible creatures, epic stalling; who DOESN'T like the airtight playing style of mono-Aether?
3. Darkness. Fun to play and very effective, with all the necessary elements to a good deck contained within this neat deck.
4. Fire. Again, very fast, and fun to play, also. Lots of variations you can try out with this nifty little thing.
5. Water. Sickeningly fast, comparable to the Earth deck, and the beautiful thing is, the damage STACKS UP and goes around largely unblocked.
6. Life. Quite fast and rather hilarious to watch your opponent being taken down by small little forest critters.
7. Death. Lots of damage, encompassing both the realm of hard-hitting dragons and poison.
8. Light. Makes great use of Blessings, and although it may not look like much, it shouldn't be underestimated.
9. Time. Reverse Times are super effective, Hourglasses speed it up, and Dragons make for good damage. Only problem is, the damage is easily stopped.
10. Gravity. The play isn't the most exciting, but Momentum sure helps in some situations.
11. Air. Only one kind of damage makes for an unreliable, although often quite fast, deck.
12. Entropy. Not the best offence, and certainly not the best defense, but at least it has some protection.
Yep, just like Plastique's, entirely open to opinion. And I agree with Plastique's last post.