One of the most overlooked but high in quality lunch places for me in the past 10 years living in Streeterville has been Lawry's the Prime Rib for a mighty fine sandwich. Its very informal while being in a formal setting. You just walk up to the carving bar and tell the man what you want (sandwich, prime rib plate, salad, etc). In addition to their prime rib sandwich (I rec on french baguette as it holds up superbly under au jus dunking) they make their own pastrami and roasted turkey breast which are also not to be missed. Slight sacrilege alert but I prefer this pastrami to Manny's (leaner but moister and more flavorful, I swear). I have had more pastrami on rye sandwiches (with swiss) at Lawry's than I can remember.
There is also a small salad bar that is included with all meals (not really a salad bar but more like a prepared "sides" bar including creamed peas, potato salad, pasta salad, several other items that escape recollection). Hushed quiet atmosphere, gorgeous dining area, great service, and they do orders to go. Its really like a weird oasis from the hustle and bustle of Michigan Ave. If you wanted to sit down and eat you could get in and out in well under 30 minutes easily as well.
If you want a proper prime rib plate they have that at prices much reduced (i don't recall the exact numbers but it is significant) compared to dinner prices. And with prime rib plates at lunch an added bonus is that their awesome (tops in my chicago reckoning) creamed spinach is included (usually extra at dinner) along with fine mashed potatoes and gravy (but no yorkshire pudding, which is still a more than even trade in my book). For the carb concious you can even ask for a double portion of creamed spinach to replace the mashed potatoes.
Did I mention endless bowls of their home made potato chips seasoned with Lawry's seasoned salt? These things are dangerous in addictive quality, although from bowl to bowl there are sometimes bowls with undersalted chips (easily remedied by a couple of dashes of lawry's seasoned salt placed at every table).
Other notes I gleaned from many visits to Lawry's
1) always tip the carver; he has been there for years and knows what he is doing. At lunch time if you are not in ultra polite company if you were lucky enought to get the rib bone, grabbing that thing with your hands and finding all the good pieces of meat is an experience not to be missed.
2) for the meat averse they also offer their famous "spinining bowl salad" for lunch. You can get it topped with turkey or prime rib as well but I actually prefer it sans meat. The Lawry's seasoned pepper at tableside really brings out the flavor of the house dressing.
3) their salad dressing is delicious (think of thousand island but much less creamy and more pop in your mouth) and they sell it by the bottle at the restaurant.
4) if you ask for an extra serving of au jus from the carver (no charge) and use it to dip the housemade potato chips into it you won't regret it.
Lawry's is most definitely *not* in the chain category, but is delicious, affordable, and not to missed if you live or work in this area.
Lawry's the Prime Ribwww.lawrysonline.com
100 E Ontario St
Chicago, IL 60611-2806