There are a couple of very nice Filipino restaurants, serving authentic Pinoy food amidst modern, comfy surroundings:
1) 7107 Flavours in Marina Square:
Try their adobo (pork/chicken), crispy pata (when available), sinigang soup, sisig (yummy but so sinful!!), kare-kare (7107's version even has crispy pork on top!!), laing (vegie in coconut creme). Maja blanca dessert is nice, so's the halo-halo.
2) Bonifacio in Kreta Ayer St (near Chinatown):