I'm not sure what to get for the blue for my ad carry rune page. A lot of guides tell me to get .15mr/level and some say 1.34mr. please tell me why you think one is better than the other. I personally think .15mr/ level is better because when you become a level 9 that's when both mr is equal. So .15mr/ level would be better for team fights, but in early game not so well?

Personally, I get flat Magic resist glyphs because I'm a really aggressive early game AD-carry and I need all the defences I can get very early on to secure a kill.

However, some people who play Ezreal or Corki get Mana regen glyphs instead of Magic resist so they can poke more often.

It's ultimately up to your playstyle and what champions you play.

it depends on what AD you are playing.

if you're playing someone like trist, then flat MR is possibly good. if you're playing a very passive champ like ashe, then MR/level is better.

in addition, you should probably invest in 2 pages so you can adapt to the situation. laning against a vayne or cait? take MR/level. laning against an ezreal? flat MR might be a better choice.

Flat AD Marks + Quints
Flat Armor Seals

Against AD Casters? Get Flat MR Glyphs
Against normal AD carries? Magic resist per level glyphs.

FLAT! Its not just the range adc its also the support. Those small damage reductions add up. I wouldnt bother with MR per level runes unless I know my opponents are going to be an easy win and someone else has me worried but even then the diff is what, 11MR?

Also, keep in mind that early power is considerably more important for runes. Every little bit can matter a lot when you're trading in early laning, but 11 extra MR at level 18 may not matter if getting caught is death regardless. Level 9 is a long way into the game, practically the end of laning phase.

But what about marks and quints? I have seen attack speed marks and MS quints. Is this only good with some ADC's?

With the removal of FoN, MR is harder to build. I personally use MR scaling because casters don't become deadly untill levels 6 and 9. By then your MR should be scaled enough to give you a little beefyness! That's how I play anyway.

General AD champion rune page as following:
Purple: flat ad
Red: flat ad
yellow: flat armor
blue: flat magic resist / magic resist per level, either one is good.

I believe I use AS blue for rane ad and magic resist per level for melee ad