Versatile Rogue deck, leaning heavily towards control but capable of some burst damage, too.
Basic idea is to keep the board clear with weapons and spells and use your minions to finish off big threats with good value trades, or hit the face. Alternatively, you can switch to aggro in the mid-game hold your spells for a burst damage finish.
The deck has come about through several small changes and iterations over a few months but has gone unchanged for a while now. I've had good success with it (no idea what the exact W/L is on it, though) and there seem to be few, if any, really hard counters to it. It seems to do quite well against Handlock decks and can completely destroy Murlocs. I'd say it has the hardest times dealing with Pallys (divine shield) and Miracle Rogue / FON Roar but those match-ups are definitely winable. I don't really get the time to play a lot, though so I've only laddered it up to rank 10 or so; I'd be very interested if anyone wanted to try it out at the higher ranks.
I'll go through the choices here, so people can swap stuff out if the disagree or think of something that does the job better (let me know);
Early game removal, with the spellpower minions out, it trades even better, allows for activation of combo effects early on. No-brainer.
2x Deadly Poison
Deals with the turn 2 2-3 drops very nicely, allows SI7 to be played on turn 4 with no coin (or Defias turn 3), can be used to proc other combo effects. This can also be devastating board clear with spellpower and blade flurry; that combo can also be used to kill the opponent with burst damage.
2x Blade Flurry
2 of these is possibly questionable but the synergy is really good and it has a variety of applications. You could possibly drop it down to 1, though. Primary use is board control with incidental damage to the opponent but with deadly poison and even just one spellpower out, it's great for dealing with things like giants and twilight drakes, too.
Obvious pick again. Kills big things, does burst damage to the opponent. Deals with things like Druid of the Claw very well when buffed. I would never use it to deal less than 4 damage and I'd be wary of using it without a spellpower minion out; if you can save it for the damage to kill the opponent, it's probably generally correct to do so.
One of the most questionable choices in the deck, possibly. I don't have Thalnos, and that may be a better bet (taking one Shiv and one Thalnos). It's kind of a leftover from when I was running a Raging Worgen stealth deck (proc the worgen, draw a card, cold blood, deal 16 dmg and stealth it, repeat; far too situational and easily countered these days). However, in this deck it does have applications; it counters the card burn suffered from playing combos (both spellpower minion + spell, and standard Rogue combo cards) and can be used early on to trade for a 3-2 on turn 2 if you coined out a Kobolt on turn 1, keeping it alive. That stacks as you play more spellpower minions, of course; you could easily end up dealing 5 with it. it also saves you using the weapon to kill a minion with high attack in some situations when comboed with an eviscerate, for example.
2x Defias Ringleader
Another questionable one, perhaps, but it slows down your opponent's tempo in the early game and therefore helps to keep the board clear. Late game, it's easy to combo and gets more bodies on the board (could save you from Rag etc) and sets up trades; don't worry about keeping these guys alive. DO NOT play it when your opponent is about to play their AOE; knife and pass the turn is better 99.9% of the time (and I'm not sure about that 0.1%). I would avoid playing it as a regular 2-2 unless it's completely necessary.
2x Kobold Geomancer
IMO, the most questionable choice in the deck, with the possible exception of Shiv. This is another one where Thalnos seems like it could be better. I actually wouldn't make that trade, though; early game, this gives you options to deal pretty much any amount of damage in an efficient way and later can be dropped to buff your spells on the same turn you play them. You can usually deal 1 dmg with the knife, 2 with the creature or Shiv, 3 with deadly poison or backstab and more with combinations of these (add in evicerate / blade flurry and it goes way up); you should have this stuff early on, if not, you got a bad draw. The Kobold just sets up value removal in a way Thalnos does not but it's still not a great creature and there may be better options. I would suggest ditching both for a Thalnos, and possibly a Leeroy if you don't want to run them.
2x Fan Of Knives
Does the same job as Shiv but also acts as a board clear against weenie stuff (or not so weenie stuff if you have enough spellpower). This is here for options, basically; is it better value to use Fan of Knives or Blade Flurry in this situation? You can even play it on an empty board to cycle your deck if you need to, especially if you have an auctioneer out; 3 mana, draw 2 isn't that bad.
2x Harvest Golem
Has similar utility to the Kobold for the trades, allowing you to efficiently deal specific damage for good value trades. I would consider taking Farseers instead, since you will hit stuff with the weapons often and you actually want the opponent to hit your face, not your minions and you may have to play for that sometimes. I prefer the Golems because the 2 attack is generally more useful (no other easy way to deal exactly 2 with the weapons if you didn't get a Backstab) and the deathrattle is useful for keeping board presence and dealing with AOE.
2x SI:7 Agent
Just straight good value; does the 2 damage and the minion itself lets you do 3 if you didn't get deadly poison. It clears the opponent's 2 drop on turn 2 with the coin and gives you board control, or kills a 4 health minion when proc'd with backstab on turn 3. Scales up depending how you proc it. It's generally OK to play as a regular 3-3 if you need to.
More removal, keeps the board clear. You won't always get perfect draws or have enough minions to boost the spells, so this deals with big problems that would otherwise kill you outright (Earth Elemental, Ragnaros, Giants etc.).
2x Azure Drake
Combats the card burn, boosts the spells and hits for 4, which adds up if you can keep it alive long enough. Reasons for picking this should be obvious.
2x Gadgetzan Auctioneer
Again, combats card burn, lets you cycle the deck, hits for 4. The longer you keep it alive, the better. It's OK to play it without also playing a spell that turn IMO but of course, much better if you can.
Sticky spellpower buffs. These are hard to remove and since they only do 4 damage, opponents usually don't see them as a very dangerous threat, so they're unlikely to use hard removal on them (they seem to think I'm playing Miracle Rogue and use it on the Gadgetzans). The 7 health keeps them alive, though; they're only really threatened by Legendaries and Giants and will help you to clear off the opponent's minions with your spells very well.
1x Cairne Bloodhoof
More sticky stuff to eat the hard removal and chip away at the opponent. I should say that, as with any of the above 4 attack minions, similar to the early game, that number allows you to deal efficient damage with your spells. 4+ Eviscerate = dead giant / Ragnaros, for example. With the right spells, you can deal 4, 5, 6, 7 or 8 damage to kill a minion efficiently. The only bigger thing you're likely to see is Ysera, and you should be about ready to go for the kill at that point (otherwise, pray for an Assasinate).
So, you spent all your damage spells clearing the board and now it's turn 8 and the board is clear. This is here for the kill, plain and simple. Hopefully they're low enough to just die at this point. If you've gotten this far and have used your eviscerates and blade flurries, Rag is your only remaining win condition; if they use a Shadow Word Death on it or something, you're pretty screwed, so play carefully. Think about what you and your opponent have remaining and if necessary, YOLO Rag. If it is not completely nescessary and you don't have an easy kill with it (rolling the dice on a 50/50 doesn't count), strongly consider your other options.
Well, thanks for checking out my deck; let me know what you think.