Just a few I can think of off the top of my head...
Mousekeeping (or housekeeping if off-site) $2-4/day
Anyone who carries your bags $1/bag
Taxi/Limo drivers - depending on where you go - $10/each way for limo driver from airport
At restaurants, 15-20% for regular service, more or less if the service is better or worse. Don't forget to tip above the cost of the bill if you get good service, but shared a meal or something so that the bill is not as much as it might have been for 2 people. Just use good judgment on this!
These are just a few of the most obvious ones...I'm sure people will post with more!