Taipei really does have some odd mainstream food. Absolutely terrible place for food IMO. Here's a photo of a very typical street food stall:
If you live there, you'll be eating that very regularly I'm afraid. After a while you'll get pretty sick of it and will become a regular at Subway.
Some of the delights I used to eat regularly:
Stinky Tofu (Fermented Tofu): This stuff absolutely stinks out the streets of Taipei. In the 7-11's it's all you can smell. Still, despite its bad reputation I got used to it and ate it regularly.
Pig's ear: The only street food place open at 3am near me was a place serving pig's ear and noodles. Not so good, but I ate there sometimes.
Pig's blood cake: Pork blood, sticky rice and soy broth. It's fried and coated in peanut flour. It's meant as a snack, and it's pretty good!
Chicken Arse: They put five chicken arses on a stick
Chicken Heart: They also do it with hearts
Taiwanese breakfast is fucking BOSS though! Bacon, fried eggs, hamburgers, pancakes, crepes, soy sauce. It's like England, America, China and France teamed up to make Super Breakfast!