Great Views, Great Food at Mix
Mix at the top of THE Hotel (next to the Mandalay Bay) has great food and a great view from the balcony (if you're lucky enough to be seated there - and if so, depending on the time of year take a coat, as it gets windy sometimes). I wouldn't call it a great value, but while it's not cheap, it's not overpriced either for what you get. Do avoid their wine list, though; good vintages, but horrendously overpriced. It's a great place to take someone who hasn't been to Vegas to see the lights spread out at your feet.
This tip has the address "Top floor of THE hotel, Las Vegas"