Looks like I'll be in Las Vegas for my birthday next year, playing Booth Bunny at an enormous conference called CES. Thought I'd better do a bit of research, given that I'll be on foreign soil...
The following is a guide to customary tipping amounts in Las Vegas. Tip bellhops from a minimum of US$2.00 - total to a dollar per piece of luggage, depending on the distance covered. Bartenders: 10% to 15% per round. Change persons: 10% of winnings when a hit on a slot machine pays off for you. Cocktail servers: if drinking for free in a casino, US$1.00 per drink. Concierges: up to US$20.00 for securing tickets to a sold-out show (no tip needed for info). Doormen: US$1.00-US$2.00 for summoning you a cab, depending on the weather. Hotel maids: US$3.00 a day, left under the card provided each day. Limo drivers: 15% of the total fare, or US$5.00 per person. Room service: 15%, minus any gratuity already charged. Skycaps: at least US$1.00 per bag, minimum total US$2.00. Taxi drivers: 10% to 15%, rounded up to the next dollar. Valet parking attendants: US$2.00, paid when the keys to the car are handed back to you. Waiters: 15% of the total cheque, up to 20% if the service warrants it. Who not to tip: cashiers, and ticket vendors working in booths.