All right, guys. I'll bite. What's this Legion business and what's a good starting point?
The few of you guys seem to be very enthusiastic about Legion and I want to know what all the fuss is about.
There isn't really a large fuss over it. It's mostly a few die hards who just love it.
It's a once popular but now niche of a niche DC property. The basic premise is that they are a super hero team inspired by the heroes of the 21st Century, in the 31st Century, but most specifically by Superman. They had a large roster and had long lasting, dynamic relationships, and explored social themes like same sex relationships far before most other books.
Part of their fun and charm is the fact that they are a team of heroes with (mostly) a single power. It was fun to pick a favorite or a handful of favorites. For such a large cast they were remarkably well realized in their personalities.
It's hard to suggest books for them unfortunately because they've had a couple reboots and their trades haven't been collected in the best fashion; for the 60s stuff there are the archive editions.
For more modern books I'd suggest Legion Secret Origin, a 6 issue miniseries that looks at the core founders and how they came together. Some famous trades include Great Darkness Saga, Lightning Saga, Superman and the Legion of Superheroes, Final Crisis Legion of Three Worlds, Mon-El: Man of Valor. For the regular series stuff, the easiest and best collected trades are probably the Mark Waid stuff that starts with Teenage Revolution. It's a 50 issue run that sees Supergirl join around midway through.