I don't see much discussion of foodtrucks on the board, but they seem to be exploding and I thought reccs for specific trucks or menu items might be helpful.
I recently tried El Floridano, and while the turkey meatloaf banh mi seems popular, I got the chicken (with tomato salsa and avocado). I really enjoyed the sandwich-- I thought it had a lot of flavor and a nice balance of tastes. My only caveat is that they serve it on a large hoagie roll and don't slice it in half (so that's worth keeping in mind if you're one of those people who doesn't like eating a lot of bread at lunch).
As I posted before I also tried the capmac truck and liked their mac and cheese.
I thought about trying Fojol Bros. but I wasn't sure it was going to be any better than the indian food at the Old Post Office. Probably try the yellow truck (bulgogi) next. Anyone try either?
By the way, there is a very handy food truck tracker (map) at foodtruckfiesta.com
12th St NE, Washington, DC