Sorry to go off topic here guys, but im leaving for Vegas in 2 days and have no idea how things work over your side of the world as far as tips go.
Question: If i catch a cab from the airport to my hotel. I use my Amex card to pay for the trip, do i tip on the Amex card? or do i carry cash and tip in cash?
Question: How much is considered acceptable?
Question: what do i tip the bag boy at the Hotel for taking my luggage to my room?
Any other tipping suggestions?

I know it may sound stupid to ask, but im just a stupid aussie with NFI.

Cheers

States wide you're looking at a norm of 15-18%. In LAS, it may be a bit higher but I doubt it because of all the old farts that vacation there.
I usually keep cash on hand to do my tipping. It's easier for the recipiant to cheat on his taxes that way and you know that his money isn't being filtered thru somebody else's fingers.

I agree with wasbeeman, cash is always more appreciated.

When it comes to cab drivers in Vegas, I would ask rates before getting in the car. You may want to ask several. No sense in getting ripped off and then tipping to boot.

I don't usually tip in cash unless the service was exemplary. I figure, I pay taxes why shouldn't they?

When we go to Vegas, we usually rent a car but at a hotel, it's usually about $4-$5 for the bellhop to take aour luggage to our room. When we have the car parked fopr us or when they get it, it's usually only a couple of bucks. We always tip in cash - it's easier & quicker. Keep a few dollar bills handy in your pocket.
Just what we do. BTW, we usually leave about $2 a day on our bed for the cleaning people. I refuse to go overboard on this kind of thing otherwise it can get quite expensive real fast.
Bear in Fairbanks

By adding the tip onto the bill and paying it by credit card usually means that the tippee (if that's a word) has to wait for his money and management will often reduce the amount by the 6% service charge that the credit cards charge. And often, the tippee is paid some sort of minimum wage and that amount is reduced by whatever tips can be tracked.