Basic Scizor (Most popular from what I've seen)
Choice Band
Choice Band Technician Adamant
Moveset EVs
~ U-turn
~ Bullet Punch
~ Superpower
~ Pursuit / Quick Attack
248 HP / 252 Atk / 8 Spe
Choice Band Scizor is famous for its ability to revenge kill opposing sweepers and scout the opponent's team with its powerful U-turns.
Bullet Punch can pick off many weakened enemies like 4 HP Gengar, who is always OHKOed after Stealth Rock damage, and Salamence with no HP or Defense EVs, who takes a minimum of 58.73% (not factoring in Intimidate). Superpower rounds off the set by allowing Scizor to OHKO several of its common switch-ins, such as Heatran and Magnezone. Brick Break can be used as an alternative to Superpower, but it won't OHKO either Heatran or Magnezone after Stealth Rock damage on average.
Pursuit is a very effective choice for the last slot, letting Scizor pick off the many frail Pokemon who switch out in fear of Bullet Punch. Starmie and Gengar will be defeated whether they stay in or switch thanks to Technician's boosts. Blissey will be really apprehensive of a super effective Superpower or STAB Bug-type attack, so can be greatly weakened by Pursuit as she switches out. Quick Attack provides a powerful priority attack that can hit Bullet Punch resistant Pokemon like Infernape, Starmie, Jolteon, and Gyarados.
Stealth Rock is absolutely necessary on any team with Scizor, as between U-turn and the entry hazard, counters like Gyarados and Zapdos will find a hard time countering Scizor over a long period of time. Using Pokemon who lure attacks Scizor resists are also fine partners (Salamence attracts Ice-type attacks, Rotom formes attract Dark-type attacks, etc.). Common revenge killers for a Choice-locked Scizor are Magnezone, Heatran, Gyarados, and Rotom-A. Bulky Water-types can switch into Heatran and Gyarados quite easily, and both Tyranitar and Blissey are good switch-ins to Heatran, Zapdos, Magnezone, and Rotom-A (as long as Tyranitar doesn't get burned by Will-O-Wisp). Firing off U-turns at the beginning of a match helps scout for Magnezone. Opposing Pokemon who can set up on a Choice-locked Pursuit (Dragon Dance Gyarados and Tyranitar, Swords Dance Lucario, etc.) should be made easily dealt with by Scizor's partners (Rotom formes deal with Gyarados and Lucario reasonably well). Weak attackers who can take advantage of a free switch-in thanks to Scizor's U-turn make great partners, Infernape and Gengar being good examples. Infernape can also revenge kill Lucario and Tyranitar with Mach Punch should they get the chance to set up.