The only part that is crowded is the block or two around the stadium when there’s a ball game. Once you get a few blocks away you can be walking down a nice tree lined side street and not even even realize there’s a game going on until you hear the roar of the crowd. The biggest impact the games have is on traffic. In the hour before and after a game traffic on Belmont, Addison and Irving Park can get congested; but if you’re walking or taking public transportation, it doesn’t effect you at all.
I’ve lived in both Old Town (which is just SE of Halsted & Armitage) and Lakeview/ Wrigleyville and vastly prefer Lakeview. It’s a bit more laid back, but still has plenty of good restaurants and bars. It’s also not as congested on a regular basis (forget about driving a car near Armitage and Halsted on a weeekend).
Good luck!