Mushashi - tepanyaki grill on paradise. Open late. Specials after midnight. Also have sushi but the steak and scallops and other combos are the way to go.
Zenshin - Asian / sushi at southpoint. Great happy hour deals. Try the chicken lettuce wraps. They also have late night happy hour.
Pho Kim Long - Chinatown. 24 hours. Mongolian beef and pho very good. WuHu noodle at silverton also has good noodle soup.
If you want to hit a buffett on the strip I'd hit the Cosmo.
Late night specials - southpoint 4.95 steak and eggs or $3.95 half pound burger and fries tough to beat.
Sushi burritto is a quick service place on Sahara that I also like a lot and it is generally healthy.