Kanom Jiin Lom Gao (ขนมจีนหล่มเก่า) is extremely popular with students, close to CMU and serves a large menu of Thai dishes for very little money. The main attraction is definitely their kanom jiin, which is more often found on the side of the street or basements of big markets. Lom Gao steps it up, with six different curries and a huge array of toppings and condiments to go with your rice noodles (read more about kanom jiin here and here). Go ahead and look in the pots, it's okay.
There are also steamed banana desserts on the table, which are delicious.