Just started the league a few weeks ago. I haven't really dived in to armor penetration yet (I know every says GET A LAST WHISPER but I'm lvl 15, and every time I try building one I get owned. By everything. I'll stick with boots 3 pots -> bloodthirster -> infinity -> The enhanced mov 3 boots w/ alactracity -> double phantom -> Tri force). Might test an extra bloodthirster over boots in the very late game if they have thornmail.

But this being as its said, I'm nearing lvl 20, and I know alot of people will begin packing in defense runes. And THAT could be problematic. At the same time, I will need a strong early game against minions; so I'm debating what will be the best combination between armor penetration and attack damage. As it stands, these are my lvl 30 masteries goal and runes goal.

http://www.mobafire.com/league-of-le...:2-280:9-283:9

http://www.finalesfunkeln.com/s3/#3MUMSGvTvdPZY

I realize my early game is going to be extremely difficult because of the way my masteries are set-up. However, as an ezreal, My Q will keep me safe from most bot-laners, except for graves, nidalee, and possibly vayne if I'm playing dumb enough. As after Level 9, my scaling runes will help to close the gap I created in masteries on the defensive side (since, via what little research I did on the matter, most people run flat armor runes in the beginning).

The armor penetration from runes and masteries will cover some of the early game, and the quintessence for AD will help a lot with early last hits.. I hope. But it would be something that grows useless as I get stronger; Would it be worth trading for 2 more armor penetration quints?

Lastly, so I can calculate some of the pros/cons either direction myself, does anyone know the armor formulas for minions? I don't like being standard ezreal, and I will fight it as long as I can xD

Thanks everyone in advance!

Edit**
Also, Before I hit 20, I'd like to have a back-up character before I start saving for runes. I'm at 4k IP and I've played one round since hitting level 15, so I should be able to buy a 6.3k IP champ and still have enough to jumpstart my runes.

Which should I get? I'm kind of stuck between these 3, but if you have any better suggestions, let me know.

Nocturne - Gotta love umbra blades, especially since I love building Attack Speed... He's got a leap, and a unique kind of pursuit skill. And it can support my teammates if a team battle goes south. Sounds really nice.

Cho'Gath - I have no Tanks, nor do I know how to play any tanks. Cho'gath would be my default if they beat me to an adc. I've got my mind on a weird Cho'gath setup that might be pretty optimal, or so I think, and I would like the chance to try it out.

Fiora - As of right now, I am going to second her. If someone beats me to the adc, I could just beast things out with her. She'd fit my play style perfectly if she was ranged =.=' If only. Gatta love her ult.

Vi - Looks like fun =3

Yup. Definitely getting Fiora.

I'm at work and can't view the links but as for you're comment on the thornmail subject a little fyi magic resist helps against thornmail because thornmail deals magic damage back at the target so stacking another bloodthirster will only kill you faster

Stacking another bloodthirster wouldn't kill me faster o.O
It'd bring my 18% lifesteal up to 36%. Yeah, I'd be taking more damage. But I'd be healing myself for 6% more damage then I take o.o

Also, I found the base armor of minions. Armor penetration doesn't help early game against them. (except the ones that spawn every 3 min)

Rule of thumb for your marks (the red runes).

If you're a jungler, use attack speed marks.
If you farm with an auto-attack, use attack damage marks.
If you farm with an ability that scales to AD, use attack damage marks.
If you farm with an ability that scales to AP, use ability power marks.

Do those rule of thumbs stay true even if you don't run any armor penetration? for example, a build without last whisper.