The Karthus thing actually happened to me in a game. I didn't mean to give the impression I blocked the whole thing. I blocked enough so Amumu lived. Barely. As far as the AP goes, with this guide you will be around 900 AP late game. Annie would Nuke better than you IMO but I doubt she would pose a problem to a decent Lux. Thanks for pointing this out though.

Hmm i like this guide but want to throw something in there, if you build Lux right, she can be a Strong AP Carry DPS on the Levels of Annie but sadly her main Supporting skills is that of just Zoning, then actuall baby sitting. Her shield doesnt come close to that of a Karthus's Ultimate FYI unless your totally fed and he has like 100 AP. lol But mainly her bubble is great for blocking that small burst damage in team fights .. and nulling out skills like Ignite ...But her main role I believe comes down to Zoning and Sniping ... but good in depth guide other wise ... thats how i play her ***