While the square taper and splined bottom bracket has taken a backseat to the press fit and outboard variety, those cranks still dominate price point and a few odd applications here and there. For that reason it's a good idea to keep a Pedro's Universal Crank Remover in the tool kit.
Constructed from heat-treated steel, this puller will outlast some of your bikes, and its integrated, ergonomic handle is coated for additional comfort when removing cranks that have bonded to neglected bikes. The Universal Crank Remover has a floating tip to ease operation, and an 8mm hex for crank bolts means there's one less tool to grab for.
Pedro's Universal Crank Remover w/Handle works with splined Octalink and ISIS Drive cranks, and comes with a lifetime warranty.