So, where does one start reading X-Men comics...?

A few months ago my nephew, who was then 13 going on 14, sent me a text asking if I could get him some Batman comics from the library where I worked, and he provided a list: Year One, Arkham Asylum, The Long Halloween, Hush, Dark Nights: Metal and Dark Nights: Death Metal. Older and/or more cynical readers might criticize Jeph Loeb's writing and elements of the Dark Nights books, but it's a solid list, and I wondered if he found it as a list of best or most popular Batman books somewhere online (I thought The Dark Knight Returns was notable absent from it, and I was a little surprised to see Scott Snyder's multiverse "crisis" series on there instead of Court of Owls). But as the guy being charged with finding those books? Easy peasy. They are all popular, fairly evergreen, in print and readily available through many different libraries in our system. Additionally, I had read all of them and was thus quite conversant in them; if my nephew liked any of them and wanted to know what to read next, or wanted more Batman (or other comics) from any of the creators, I could recommend other books until he was sick of hearing me talk.A few weeks ago, I got a much scarier text from my sister/h...