#10 - Night Reaver - The Night Reaver is a two-handed axe with 20.6 DPS, and a chance to strike the target with a 60-90 damage shadowbolt upon hit. It is a decent weapon for melee classes in the 10-19 twinking bracket, particularly Paladin's who cannot dual-wield. It is a zone drop from Shadowfang Keep, which is recommended for level 20 and above. You'll probably need to get a run-through around or before level 16 so as not to surpass the bracket while you're doing it.
#9 - Twisted Chanter's Staff - The Twisted Chanter's Staff is one of the top level 19 twink caster staffs available. It's a world drop, and very rare at that. Most of the time you can find one on the auction house, but expect the price to be high!
#8 - Bow of Searing Arrows - While 39 isn't as popular of a pvp bracket as 19 and 29, there is one amazing item that any 39 twink Hunter must have - The epic Bow of Searing Arrows. It has the highest DPS as well as an "on hit" that deals extra damage. It's a rare world drop and one of the lowest level epic items, so prices are high and availability is low.
#7 - Blackend Defias Armor - One of a few highly coveted level 19 twink armor pieces, the Blackened Defias Armor also drops off of Van Cleef in the Deadmines (along with Cruel Barb). This could translate to quite a few Deadmines runs for a Rogue twink. The Blackened Defias Armor is leather, and well suited to Rogues, Feral Druids, Hunters, and Enhancement Shamans.
#6 - Feet of the Lynx - Feet of the Lynx are leather boots, extremely highly coveted by level 19 twink aspirants. They are a world drop, and extremely rare, meaning they often cost several hundred gold.
#5 - Engineering Goggles - Many twinks choose to be engineers, because the goggles that one can craft have good stats, low level requirements, and are the first head-slot items available. Not only that, but the little crafted bombs are fun too.
#4 - Thermaplugg's Left Arm - Thermaplugg's Left Arm is a 29 twinking item for Warriors or Paladins. It's a two-handed axe that a ton of Strength and very high DPS. It drops in Gnomeregan, and will likely require you to purchase several run-throughs.
#3 - Master Hunter's Rifle / Bow - The Master Hunter's Rifle and Bow are great items because, even though they are Uncommon quality, the vastly out-class all the others in the level range. The reason for this is that this item is a reward from a quest that is incredibly difficult to complete at the lower levels. You can acquire this quest at level 28, but will need the help of a higher level player to complete it.
#2 - Cruel Barb - As discussed before, the Cruel Barb is one of the best and most widely known twinking items. It drops off of Van Cleef in the Deadmines, increases attack power, and therefore is the object of most Rogue's and Warrior's undying adoration. Getting this item is incredibly difficult, because it drops very rarely and you need two of them to truly kick butt.
#1 - Deadman's Hand - Added in patch 2.3, when "old world" dungeons received a significant item overhaul, the Deadman's Hand is an epic quality ring that increases Stamina and has a chance of freezing someone in ice that strikes you in combat. It requires level 29, so is therefore one of the most amazing twinking items that ever existed.