If we are talking 4th Generation, The correct answer is Electrode. Its speedy, the other two are slow. Its main use, however, will be setting up weather/screens and not battling though. And Exploding. Because of No Guard + Dynamicpunch combo, Machoke probably comes in second (especially if you can evolve it into Machamp, use the Rom's link up feature hint hint). Arbok is third, because its movepool stinks and its stats are meh at best.
I'm guessing you want to know this for a let's play or an on cart playthrough. All right, to sum things up:
If you are doing a playthrough of fire red/leaf green, go with Electrode, then Arbok. Go with Machamp over Arbok if you can evolve it.
If you are doing a playthrough of D/P/Pt/HG/SS, go with Electrode and Arbok, because Machoke, despite being better than Arbok in 4th Gen, doesn't get Dynamicpunch until 51. Go with Machamp over Arbok if you can evolve Machoke, but go Guts > No Guard.
Hope I helped.