Depends on your playstyle. I've added WoA last because you probably won't build it. The game will be long-over.

To stay in lane I usually carry about 5 healh potions around. If you prefer spellvamp Hextech Revolver is a fine choice.

I've shown an itembuild or two, but there are many viable ones! I really believe it's less about item build than the way you use your skills.
Also, I build according to what I encounter. For example, sometimes I do not build mejai, and sometimes I build Abyssal as third item.

Oh ummm.... I meant hextech revolver btw :-)

Very nice guide. We need some good LeBlanc guides out there. Reading this I might even pick her up. Hope you get to finish your guide soon! One question: why do you get Will of the Ancients so late? Or do you get hextech gunblade earlier for laning?

The guide isn´t quite finished. I´d like to cover all there is to cover about LB, but I´ve been working for hours now so it´ll have to wait ;)

What I'd like to know is the following... I really don't want to bore people with obvious ****. So...
Do you want the items sections even more extensive for example? Want me to explain why Lich Bane is a bad choice? Or do you think I should include Ghost in the Spells section? I mean, we all know Ghost right?

Tell me what you'd like to see in a guide and I'll adjust the guide accordingly ;)

I hope you've enjoyed the read so far