Nothing annoys the non-Casual player more than to lose to the Casual player by an alternate victory condition.  Not that I would ever build a deck to exploit this fact.  No, the deck I want to discuss is based in the sheer fun of winning using Poison, something that many players feel is highly unlikely.  And frankly, before the Time Spiral block, it certainly was.  However, now a poison victory is well in the range of the casual MtG player and a solid deck should most certainly be a part of the casual player arsenal.  What makes poison so much better now?  Two cards: Virulent Sliver and Snake Cult Initiation. 

They rock hard!  Let's put them in a poison deck and see what happens:

4 Virulent Sliver

4 Snake Cult Initiation

Poison is great, but it gets totally awesome when it is untargetable and unblockable.  Hence, the value in adding the following pieces of equipment into the deck:

4 Whispersilk Cloak

It is always good to give one Virulent Sliver shroud as soon as possible to make all other Slivers (and Changelings) poisonous.  However, after the first few turns, think about getting a Snake Cult Initiation on creatures prior to equipping them with the Whispersilk Cloak.  Sure, everyone thinks they won't make that mistake- until it actually happens.  Luckily, you can always re-equip.

Now nothing goes better with poison than more poison, so adding more slivers will rapidly multiple the effect of any Virulent Silvers you get out early.  Plus, the Gemhide Slivers will provide the valuable black mana needed to cast the Snake Cult Initiation enchantments.  Of course, a Changeling is every bit as good as a Sliver in the current environment so I use the following:

4 Gemhide Sliver

4 Woodland Changeling

3 Might Sliver

4 Avian Changeling (sliver with evasion are always cool)

Now, since the deck already has a Sliver theme going, it doesn't hurt to milk it a little bit...

2 Essence Sliver

2 Harmonic Sliver (a dead card until your opponent plays some targets)

Now we need a few cards to help poisoned tipped creatures plow through the opposition or remove it altogether...

2 Pentarch Ward

3 Oblivion Rings

Not exactly sure why I decided to round the deck out with these final two cards.  I think I just had it in for the milling Merfolk decks that were all the rage when Lowryn first came out.  This certainly gave them something to think about.  I like them in the deck as I can always just use them to slip deceased Virulent Slivers back in the deck and draw a card.  Feel free to take the deck in another direction that you feel makes more sense.

2 Gaea's Blessing

As for the mana base, I went with the following:

13 Forest

9 Plains

2 Swamps

Certainly a case can be made for throwing in 4 Terramorphic Expanses or other lands.  I chose not to and still managed to get excellent results.  You pretty much know by turn 4 whether you will win or not.  Luckily, the answer is usually yes, but if you Virulent and Gemhides are smoked in short order and you can't quickly replace them, then your future becomes quite dim in a hurry.

I'm playing with 62 total cards.  Sure, there is probably a 60 card version that is even better but I'll leave it to the reader to create it and his/her own swath of terror using the concepts of this deck.

This deck will definitely always give you a decent chance to win and a few opening draws will positively smoke any opponent. 

Did I mention the cost of the deck?  The full 62 card version above runs about 5.78 tickets.  A mere pittance for a deck that deserves a place in every casual MTGO player arsenal.  And if you drop the two Gaea's Blessing you are down to a mere 3.78 tickets.  There aren't many decks more competitive at such a ridiculously low price point.  And you'll find no sweeter win than a poison win!