Up until now for Mexican in Williamsburg I've always had to walk west over the BQE to get good Mexican (places like Zocalo, Buffalo Cantina and Taco Chulo) so I was very happy to discover Taco Bite which just opened on Rodney by South 4th just a block from my apartment on Keap Street.
The first thing that hits you is that the food is authentic and tastes great. My "regular" on the menu is their vegetarian burrito which always includes fresh veggies in addition to the usual rice and beans and always includes some chips and a very sharp salsa. I haven't tried it yet but they also have fried ice cream on the menu which looks amazing. In addition to the usual Jarritos they also have margaritas and espresso too. The decoration and service is nice, so you wouldn't mind hanging out there with your friends for a relaxing afternoon.
I haven't checked it out yet but they also offer a breakfast menu which includes non-Mexican treats like waffles and pancakes (they open at 7am if you're an early bird). Most nights they're also open late until 10pm, and on Friday and the weekend they're open until 11pm — although on Mondays they're closed. If you like to order in they have free delivery for orders over $10 (and they accept credit cards):
Taco Bite Restaurant
310 South 4th Street (by Rodney)
Brooklyn, New York 11211