A recent blog entry from Vegas.com gives their list of favorite late-night eateries for visitors with the munchies.
The restaurant at the top of their list, Carnegie Deli (at The Mirage), is on my list for late-night dining as part of my upcoming solo trip. I'm looking forward to trying their Shrimp Salad Sandwich - YUM!
Of the others on their list I've only tried Grand Lux (at The Venetian), and I have to say they certainly do have a widely varied, delicious selection of appetizers and entrees. They are owned by Cheesecake Factory, so expect giant portions just like you'd get at CF. It definitely makes sense to share if you can.