If you don't mind the atmosphere, I'd recommend Rose Market on the "other" (west) side of Castro St near El Camino. It's a persian market with great, fresh grilled kabobs. The kubideh and chicken are both very good, served with lavash and fresh mint and parsley.
You order at the cash register, and there are just a few plastic tables outside. But it's cheap and unique.
I also second Amber Cafe, the "fast food" branch of Amber India.
So depending on what you feel like eating - there are places on Castro and off of Castro:
Maru Ichi (on Castro)
Ryowa Ramen (on Villa before Castro)
Don Giovannis (on Castro)
Frankie, Johnny, Luigi too (on El Camino, north of Castro)
Sushi Tomi (on Dana south of Castro)
Sono Sushi (on Castro)
Spice Islands (on Hope (parallel street south of Castro))
Hangen Szechuan (on Castro)
Shanghai Taste Delight (on El Camino north of Castro)
Hope this helps!
Petit Bistro on El Camino near Shoreline serves French food. Next door to that is El Paso Cafe (Mex/full bar; cash only). Vive Sol on ElCamino near Rengsdorff serves good Puebla style Mex. Hunan Home's (Chinese) is also near Rengsdorff. For lunch, give Amanor (Armenian) deli a try. They're between Castro and Shoreline and bake their own bread.
West El Camino Real, Mountain View probably runs for a couple of miles... At the Northern end of the stretch, you have Chef Chu's (@ San Antonio Rd) and at the Southern extreme, In-n-Out Burger (@ Grant Rd).
Along the way are two good Indian restaurants: Amber India and Passage to India. Haven't tried Amber Cafe.
I used to go to Garden Fresh for vegetarian Chinese; it's good if you want to avoid meat, but for those accustomed to the full range of Chinese cooking, the sauces may seem somewhat one-dimensional.
Of course, if you do venture down Castro St., it's a bonanza.
Most will probably recommend the butter chicken...which I don't find too remarkable. A real gem on the menu though is the goa fish curry. It's perfectly browned, yet moist pieces of halibut simmered in a curry sauce. It's amazing and a welcome change from the reliable standards one ususally gets.