Two of the very best (and most interesting/creative) restaurants in the entire Chicago area are nearby.
Just south of Highland Park is Michael, in Winnetka. I eat at a lot of different restaurants in the city and suburbs; Michael is one of the few places I keep going back to. At least three of the six best meals I've eaten in the Chicago area in the past five years were at Michael. I've posted several reports in the topic at www.chow.com/topics/351457
A bit north of Highland Park is Inovasi, in Lake Bluff. Chef is creating some mighty fine food there, as well. As an added bonus, it's remarkably inexpensive. I've posted reports in the topic at www.chow.com/topics/687962
Highland Park itself has four new upscale restaurants: Second Street Bistro, Abigail's, M, and Benjamin. I have not yet been to the first two. I had a very nice lunch at M last week. I had dinner at Benjamin last month and I do not recommend it; the food was just okay and the service was lacking.
Other places in and near Highland Park that are worth mentioning include Carlos (Highland Park, fine dining, will be re-concepting after New Year's); Cafe Central (Highland Park, French bistro); Froggy's (Highwood, French bistro); Gabriel's (Highwood, Italian/French); and the Curry Hut (Highwood, Indian).
429 Temple Avenue, Highland Park, IL 60035
310 Green Bay Rd, Highwood, IL 60040
64 Green Bay Road, Winnetka, IL 60093
455 Central Ave, Highland Park, IL 60035
Froggy's French Cafe
306 Green Bay Rd, Highwood, IL 60040
410 Sheridan Rd Ste 1, Highwood, IL 60040
28 E. Center Ave, Lake Bluff, IL 60044
1849 2nd St., Highland Park, IL 60035
675 Central Ave, Highland Park, IL 60035
493 Roger Williams Ave, Highland Park, IL 60035
Second Street Bistro
1825 2nd St, Highland Park, IL 60035