I think Bucktown and especially Lincoln Park might be a little young for you. Lincoln Park is a college neighborhood (DePaul University, to be specific) with a lot of "just-graduated" folks there. Bucktown has a mix of "would have just graduated were I not too hip, indie and cool to attend an Establishment institution like college" folks with a mix of 30s professionals, both singles and couples. Of those three, I think Lincoln Square may be a little more your speed -- nice, trendy, upscale, but more mellow than "partytime!!" (Lincoln Park) or "Nose Rings!" (Bucktown). Another neighborhood befitting of your age bracket is Andersonville, but unfortunately that would not be a particularly convenient commute to Rosemont. For that matter, neither would Lincoln Park.
Lincoln Square is pretty convenient to the Blue Line -- hop either the Irving Park, Montrose or Lawrence bus to the Blue Line and you're on your way to Rosemont. But while it's convenient, it might be a little time-consuming because those arteries get pretty clogged during rush hour. Therefore, an alternative might be to live in a neighborhood closer to the Blue Line, such as Irving Park, the west edge of Albany Park, or Jefferson Park. There's not a lot going on in these neighborhoods -- generally more family-oriented than nightlife-oriented. And when you want to access dining/entertainment/nightlife options, you're only a short bus ride or train ride away from several options. Plus rent and/or property is cheaper.
Another note on your commute: the Blue Line northwest of Addison Avenue is a complete disaster right now. Whatever you think your commute time should be, double it. Seriously. Average train speed from Addison to Rosemont is about 10mph right now. Supposedly this will be fixed by early next year; we shall see.
Finally, what is your field specialty? And does your department/firm need an intern?
