In Lakeview, between Sheridan Road and Diversey, is an outstanding little neighborhood restaurant called Miss Asia. The Duck Curry with Lychees, pineapple and basil cooked in red curry is succulent, bursting with flavor and only $9.95. Although I think their takeout business may be bigger than their eat-in, the decor is actually beautiful with sculptures not only on the walls but between tables. Very romantic. They also have Camboidan dishes like Beef in Tamarind Curry (with pumpkin and pineapples) and Indian dishes like samosas and grilled fish with "pakistani spices." I'm salivating as I write this ...
434 W Diversey Pkwy, Chicago, IL 60614
If you wanna condense noddles with curry, and try other things, you might wanna look into a dish called khaosoi or khaosoy. It's usually a coconut milk curry with deep fried noodles. I think tac makes a very respectable version of this. When I feel like having a "comfort food" meal at Tac, I usually have:
Thai fried chicken
Khaosoy or panang curry (a little extra spicy)
This will generally STUFF two people and have a good amt of leftovers. It will easily feed three.
Just to condense Nsxtasy's comment: you're gonna have to travel(from O'Hare) for the great Thai food Chicago-proper(not suburbs/not Evanston) has to offer. I like TAC, Spoon, Opart, and Ros Ded...the latter three are all within blocks of one another in Lincoln Square.
Well, there's "best", and there's "best"... ;) There are also differences in location. So, without further ado...
IMHO the very best Thai restaurant in the entire Chicago area is Thai Sookdee, in Evanston. The best tom kha gai in the area, wonderful panang curries, and just everything I've had there is consistently excellent. Evanston is the first town north of Chicago on Lake Michigan, about 30 minutes driving from O'Hare. So if you want the very best Thai food we've got, this is the place:
1016 Church St.
There are several places in the city of Chicago that people consistently recommend, including TAC Quick, Spoon Thai, and Sticky Rice. I think TAC Quick is the best of these three, but its tom kha gai isn't all that great (seems tomatoey). Overall I would say it's pretty good, but I like Thai Sookdee (above) a lot better. All are 25-30 minutes driving from O'Hare (assuming it's not rush hour).
3930 N Sheridan Rd
4608 N. Western Ave.
Chicago, IL 60625
(773) 769 - 1173
Sticky Rice Thai
4018 N. Western Ave,
Chicago, IL 60618 USA
Another place I've heard people recommend, but is the one place mentioned here I have NOT been to (and thus will not comment on how good it is), is Elephant Thai. Elephant Thai is quite close to O'Hare, only 10-15 minutes away.
5348 W Devon Ave
In the other direction, away from the city, AltThai in downtown Arlington Heights is very good, as good as TAC Quick (but again, I like Thai Sookdee better). Trendy modern decor (like TAC Quick). 15-20 minutes driving from O'Hare.
40 S. Arlington Heights Road
Arlington Heights IL 60005
Another place that's closer to O'Hare (10-15 minutes) is Siam's House in Niles. I ate there and I really did not like it at all, and would not recommend it.
7742 N Milwaukee Avenue
Niles, IL 60714
Two other Thai places I'll mention (out of maybe 50 or so Thai restaurants I've tried in the Chicago area) are Ruby of Siam in Evanston and Skokie, and Thai Pavilion 2 in Skokie. Both can be very good, but are occasionally inconsistent; sometimes they're excellent, other times they're just okay. If you're considering eating Thai in Evanston or Skokie, Thai Sookdee (above) is easily the best of the dozen or so Thai places in those two towns, but if you'd like to try another, these two are also worth considering.
Ruby of Siam
9420 Skokie Blvd.
Thai Pavilion 2
4654 Church St.