According to Rating Battles results on the Gloabal Link, people are more commonly using Grass Pledge and Energy Ball, but Sceptile is most victorious with Leaf Storm or Leaf Blade and Rock Slide. Purely based on the GL data and Smogon, I'd probably go with a set like this:
Sceptile @ Sceptilite
Naive
Overgrow
252 SPA, 252 SPE, 4 ATK/DEF
-Giga Drain
-Rock Slide
-Focus Blast/Earthquake
-Leaf Storm/Earthquake
Giga Drain will give you stab and healing without the horrible reduction in special attack, but Leaf Storm can be there for pure power. You'll have plenty of type coverage between Rock Slide, Earthquake and Focus Blast. That Rock Slide will help with any flying, ice, bug or fire types that would otherwise hinder you. Hope that helps.