Woot! I love math, so I've researched my favorite hero -$- LUX -$- The lady of luminosity and her wonderful double rainbows is both fun and powerful. Played agressively, you can pin opponents to their tower, and you have a wonderfully undervalued defensive shield ability. Play her at max range, use the auto-attack if you can, but realize that late game that is a sentence of death usually.
Runes to build up mana regen are pretty important. The archangels staff is about the only item I can rely on for enough MP/5 consistently. Cooldown Cooldown Cooldown is the primary limitation of Lux abilities. Buying AP out the nose is actually NOT how I suggest getting the most out of Lux. You want to use her abilities to snare and stun as well as do damage. I consider the stun to be the best ability she has. If it does 60 damage or 260 damage, in the late game, what makes it great is the 2 second stun. AP does some good, but cooldown does a lot! In fact by leveling it up you double the cost of the spell for no increase in stun. Cast time 15 sec to 13 sec not a big difference. Level the shield! Sooo undervalued and its cost does not rise, just its effectiveness!

forgive me if I consider Lux getting a critical on her low attack damage once more out of every 151 attacks negligible .. that said, the point is changed

GTFO on the smite, she uses her auto-attack very often so grab the 1 point in crit...

Putting a point elsewhere doesn't really help Lux out much if you're doing 5/0/25. Actually I'm more inclined to use my standard 0/9/21 build with her but this one is more affective in terms of adding to her AP/Magic Pen. I might want to tweak the masteries a bit...

Why do you take improved smite?

nice build but some pics would be nice to have and i like the DFG idea it is great since once their binded their screwed then u can slow and fire your lazar then
+1
oh ya i went 8-1-3