"A shady island in a sea of rice" is this little shop/restaurant's slogan. Aside from the sandwiches being amazing (especially by Chiang Mai standards), I'm also amazed the place has been such as success over the years, obviously aiming mostly for the foreign market but not being in a very touristed location. I think this is also the first place I review with its own website at http://www.amazingsandwich.com/ though my pictures here look better if I may say so myself. 8-)
Aside from sandwiches and subs they also do breakfasts and general Western snacks and pies. When ordering sandwiches you order from a pre-printed order form piece of paper where you tick off the type of bread, choose one or two kinds from several meats, one or two kinds from several kinds of cheese, and add veggies, herbs and sauces.
They're not stingy with the portions either. The baguette I ordered at 80 baht was actually a bit too much for lunch.. Chiang Mai doesn't have a Subway yet, but I'm willing to bet this place has the edge in taste, price and value!
The Amazing Sandwich is located on Phrapokklao Road, a couple of steps North of the Thai Airways office. If you had the dubious idea of trying to go to Thai airways at lunchtime when all their staff are also having lunch, you can get the queue-number at the Thai Air office and then go eat at Amazing Sandwich and come back with time to spare! :-S