I love
Superdawg. It's on my way home from O'Hare (Nagle to Devon to Peterson), and when I've been on the road, it's easy to stop to get dinner for The_Wife and The_Kids. I prefer mine with everything, and the fries are best eaten on the premises. And the chocolate shakes are fantastic too. When The_Kids get a little older, we'll take them there since it's a drive-in, complete with carhops.
A little closer to home, we go to Wolfies (sorry, no web site), but I usually get the gyro since I'm addicted to the damn things. The hot dogs are great there, too, though.