If you want to live in the city, you probably want the north side, then within the north side, it sounds like you want something near the lake. Lincoln Park is mostly youngish professionals and college students, it’s right on the lake, it has a lot of large, gorgeous parks. It has the nationally known Green City Market farmer’s market. It’s a fun place to live. There’s nearby tennis, a marina, it’s basically got everything. It’s also pretty expensive. It’s considered one of the nicest parts of the city. There are also a lot of kids, but you can easily work where choose to be kid free and old person free. Right now (I’m moving to Pittsburgh in July), I’m living in a really nice, family owned building that’s all adults, right on the park. It’s just all how you work it.
Honestly, I’m most familiar with Lincoln Park, Ravenswood, Andersonville, and Lakeview. They would probably all be fun options—you’re less likely to find a nice condo in Ravenswood—it’s more houses or apartments. Lakeview and Lincoln Park are on the lake and most likely to give you really good lake access. Lakeview is probably less expensive than Lincoln Park (because the good rule of thumb is the further away from the Loop, the less expensive stuff gets until you hit the burbs).