Fat rice is by far my favorite restaurant in the city.  Get the Diabo and the Fat Rice

A few of my favorites El's Idea, Longman & Eagle (dinner not brunch) , Goosefoot, Schwa, Piccolo Sogno are just a few of my favorites. Little Goat has a great brunch.
Fat Rice as mentioned above is good, almost went their this evening.  

Geja's Cafe in Lincoln Park right off of Lake Shore Drive.

I second the Fat Rice recommendation! It's normally pretty busy when I've gone there, but the vibe is so cool. If there's a wait, they typically suggest grabbing a cocktail at "The Ladies' Room", their adjacent bar. It's kind of speakeasy style and super cool, even has card games to play!  

Altiro in Roscoe Village has impressed everyone that I have taken there and I just recently enjoyed a date at Bulerias on Ashland they have awesome sangria.  

I love Geja's! It's north of downtown (and so am I) so I have had a couple dinner dates there.  My favorite north side spot is Kitsune.  My favorite steakhouses are Gene & Georetti's, for an old-school atmosphere or GT Prime for a cool more modern date spot.

I'll have to check this out I'm often hanging out in RV. Thanks for the recommendation!

Love Geja Cafe I always stop in before a show at Park West. Even if I'm not eating they have an excellent wine selection.