Staying at Lisle / Napperville Hilton Aug 18 - 22
From the Hilton Lisle, you are surprisingly close to dowtown Glen Elly and Wheaton. in Glen Ellyn, Mykha's (white tablecloth vietnamese) is a personal favorite. Very do-able, if you have a car (and probably not bad by taxi).
Here's a post on West chicago, which also picks up Wheaton & Glen Ellyn.
476 Forest Ave, Glen Ellyn, IL 60137
NSXTASY's comments are valuable on the places he mentions, but do not rely on the attached links to earlier posts as they date from 2006 to 2008 and a lot of changes have taken place in Naperville. I noted one comment about Timpano, but that place went under more than a year ago.
I fully agree with Allgauer's (we eat there at least once a month and I find the duck breast outstanding). Parker's is also good but about 7-8 miles away (that should not stop you). If you go to Jefferson avenue and Washington St in Naperville, you will have a wide range os places to try, as nsxtasy indicates. Catch 35 is good as is La Sorella di Francesca. Heaven on Seven has never been a favorite of mine, but they do have good cajun style food. About 1 1/2 miles from the Lisle Hilton is Laurel Mediterranean Grill (Iroquois Mall in Naperville) where the serve excellent Turkish dishes and other middle eastern fare.
In the same mall is Joy Yee Noodles, which offers pan-Asian dishes prepared quickly and well for a very modest price. Good food there.
there are other places worth trying in Naperville. If you can say what cuisine you are interested in especially, I can give you other recommendations. Naperville is not a culinary desert
The locations seen below did not come from me.
100 S Washington St, Naperville, IL 60540
Heaven on Seven
600 N Michigan Ave, Chicago, IL 60611
La Sorella di Francesca
18 W. Jefferson, Naperville, IL 60540
Joy Yee Noodle
1163 E Ogden Ave Ste 707, Naperville, IL 60563
Allgauer's, the restaurant right inside your hotel, is very good. It's not just a hotel restaurant; many locals go there as well. They're well known for their Sunday brunch, and they might still honor the coupon for free dessert Mon-Thurs on their website at www.hilton.com/en/hi/hotels/hotelpromo.jhtml?ctyhocn=NAPHIHF&promo=dining
Parker's on Highland at I-88 in Downers Grove is excellent, and has some of the best seafood anywhere in the Chicago area. They also serve authentic (officially certified) Neapolitan-style pizza. www.parkersamerican.com
Sugar Toad is the most upscale and most creative restaurant in the area. www.sugartoad.com
Here are more good choices in the vicinity. Good steakhouses include Sullivan's www.sullivansteakhouse.com Capital Grille www.capitalgrille.com and Morton's www.mortons.com Heaven on Seven is good for cajun/creole cuisine. www.heavenonseven.com Although Parker's is my favorite, two other good seafood restaurants are Hugo's www.hugosfrogbar.com and Catch 35 www.catch35.com For authentic Chicago deep-dish pizza, go to Lou Malnati's on Jefferson Ave in downtown Naperville; call ahead with your pizza order to avoid waiting 30-45 minutes while seated for your pizza to bake. www.loumalnatis.com
All of the above except Malnati's accept reservations on Opentable.com
Here are some previous discussions with more recommendations in that area: