Originally Posted by MechaKameleon
Wow. That's a lot to remember. Mind you, it was helpful.
The thing is I don't understand how to make a good build and how impacting items are. Like some people say, "Don't go with Shurelya's." and others are like, "No no! Shurelya's is awesome!" In the end, I don't know whether or not I should go with it because people say different things and I don't even understand how Shurelya's works; I just go with what people tell me to! I don't know whether or not certain items are helping me or how items with low Armor, MR, or whatever are still beneficial even though it appears that its stats are low.
Anyways, if there were such things as LoL classes, I'd so be attending them. XD
Most items are situational, which means you need to learn to change your build based on the situation. Examples would be taking Athene's when you're either being counterjungled or you have a blue-dependent mid like Anivia; taking Frozen Heart against an attack-speed heavy enemy team; taking Quicksilver Sash over Force of Nature to counter suppresion champions like Malzahar.
I recommend looking at some articles on the LoL Wiki if you havn't yet: http://leagueoflegends.wikia.com/wik...'s_Reverie
As for Aegis of the Legion, it's a good item, and it provides a lot of benefits to both you and your team, it's simply better used on your support due to the range of its aura.
Shurelya's is especially important for Solo queue, because you'll be using it for initiating. If you're queuing/teaming with the support, or you have some form of communication with them, you can tell THEM when to use its active and take a different item for yourself. Of course it becomes a useless item if you don't actually use its active :P