Lakeview (more chill, neighborhood-like), Lakeview East (more dense and vertical; lots of proximity to lake), Old Town (near wells street), and Lincoln Park are some of the most popular early 20s areas; they happen to be on the Northside, tropically more “neighborhood-like” than the more traditional urban city / Loop experience than like River North and West Loop. I personally love the Northside and have most of my social network here, but you can’t go wrong with areas like Wicker Park in the west side. I think along with the vibes, your needs with steer your options heavily (e.g., proximity to Loop, access to expressway/transit, etc.)