If you like Japanese, there are three to choose from on 40th from Mad to 5th. My favorite is Yagura, closest to Mad. Ave. Cheap and good. They have hot foods and pre-wrapped sushi rolls.
Also there's a good gyro place on 39th & 38th on 3rd. They also have chicken. Sorry I can't remember the name but it is on the West side of the Street. Haven't worked in that nabe in a while.
There are a few places on E. 45th, within walking distance, that I like:
Oms/b (for omusubi)
Aburiya Kinnosuke (decent set lunches, but a bit weak on the unagi)
Bayan Cafe (Filipino)
And Peter's suggestion of Boi to Go is a good one.
213 E 45th St, New York, NY 10017
156 E 45th St, New York, NY 10017
Thanks for the recommendations!
A couple of other places I've found around the area: Crisp, which makes good falafel with homemade pita (corner of 3rd and 43rd), and Sophie's Cuban (Lex between 41st and 42nd) - love the goat stew, chicken soup, baccala, and plantains. Both are reasonably priced.
I will definitely try the coffee at Juan Valdez Cafe - I've passed by a few times but didn't know what to make of the place.
If you can walk down to 34th, Ali Baba. If you can walk up to 49th between 3rd & Lex., both Ise and Caffe Linda. For takeout, I find the salad or noodle bowls at Boi to Go better than the banh mi. Blarney Stone on 3rd between 44th & 45th. Fagiolini is OK. I work on 55th & 3rd, so I'm more familiar with north of 50th. 53rd between 2nd & 3rd has a number of good choices: Ariyoshi, Marrakesh & Tadka. Wu Liang Ye on Lexington & 39th isn't as good as their other branches, but might be worth a try. Juan Valdez Cafe at 480 Lexington if you want great coffee and either sweet arepas or pan de bono (cheese bread).