Not a finished build...

Only 2 late game items

There are only 2 last items in this build...

Thanks for the comment!

First of all, sorry about the text, I got a little carried away and I'm not sure how to fix it. Oh well.
Second of all, like I mentioned, I'm not exactly sure how to approach the later items. For me, it is entirely a spur of the moment kinda thing in terms of what I'll buy next. Maybe I'll just mention some of my favorites or something.
Third of all, I'm completely fine if players want to skip early Shurelya's and go with Aegis. Personally, Shurelya's is an item I want as soon as possible, even if my team could benefit a lot from Aegis. Maybe I'm just selfish. I find I can influence my teammates much more with Shurelya's as it serves as an indicator of my intentions, a.k.a. if I activate it and run towards the enemy my teammates seem to follow more often.
Forth of all, Ezreal does appear to be a lackluster champion in terms of AD carry nowadays. I just put him there because his ultimate becomes extremely simple to use with Amumu around. Other AD carries do have moves that complement Amumu, such as Corki's AOE skills, but I just like the simplicity of Amumu ult followed by Ezreal ult. Its a a devastating no brainer.
Fifth, I used to run magic pen myself with armor quints. I moved away from magic pen solely because the magic pen does nothing to speed up the jungle. I much prefer having a safer jungle by adding armor. So by using Armor marks, I can free up the quints to open up much more customization. If you want movement speed, go for it. Armor, sure go for it. Hell, even health. BTW, I'm not sure what path you take with boots, but in my experience it is a mistake to counter-jungle as Amumu, which is where boots become most handy. Wouldn't a more unpredictable jungle be achieved by getting a defensive item so you have the sustain to change paths if necessary or desired?

Solid guide. Few things to think about:

- There's heeella text blocks. Makes the guide kinda annoying to read through.
- I'd maybe put suggestions for some of those situational item choices for later in the game.
- Would like to see an earlier aegis as an option over shurelya's if your team is struggling. Even those items are kinda variable.
- Ezreal doesn't really belong in god tier imo. There are plenty of ad carries capable of taking huge advantage of Amumu's ult (eg corki, ashe, mf, graves to a lesser extent). Ezreal is a decent champ, but doesn't really have the damage to be placed in a tier higher than the other ad champs.
- Different options in runes could be helpful. I for one run magic pen reds, and armor quints in many situations. This helps with my damage later, and (combined with boots 3), give me a more unpredictable and faster jungle.

Anyway, though, it's a good guide. And good job turning on comment to vote. ;P

Hey, thanks for the comment! I think I've addressed most everything you mentioned, except for visuals. I'll try to work on that at some point.

Pretty good guide, can't remember the last time I read a well-rounded Amumu guide. The chapters are well summed up giving knowledge of the systematic of the game rather then a one-way hole view point. You should try to get hold of some screen-shots to help illustrate certain explanations and to give some more "light" to your guide. Just some pointers below.

Introduction / Pros & Cons

I'd make the sub-headings more recognizable though either increased font size, colour or underlining, bold etc rather then just a plain plus or minus.

Runes

I'd include Greater Mark of Armor as another choice for the Marks if you're wanting to become extra tanky or the enemy team consists of many potent ADs. Not sure if you should really include Greater Quintessence of Gold seems a bit overkill in terms of gold generation, your not a support after all and you'll be clearing camps rather fast as the game goes on. Nevertheless whatever the case you should probably include: Greater Quintessence of Magic Resist and Greater Quintessence of Ability Power.

Skills

You should consider giving more insight regarding Bandage Toss seeing as it is one of Amumu more variable skills. Mention of utilizing it as an escape mechanism (Bandaging jungle creeps or minions to get away from a nasty situation) and an interrupt (Spot that Fiddlesticks over the bush on top of your ward on the verge of casting Crowstorm? Shut him up with some toilet paper).

Items and Progression

I'd expand on the other possible items by giving an account of when you for example would choose them in what situations and your view of the item.