We've always tipped housekeeping no matter where we stay. I always thought it was a given, even though, of course, it's a personal choice based on how well they took care of you. Most hotels I've stayed at even have special tip envelopes to leave the tip in.
We tip at WDW but used to leave it at the end of our trip till we read posts here about tipping daily in case your mousekeeper changes. We also printed out the special mousekeeping envelopes that a nice poster here provided with Mickey or Minnie or Goofy etc... on them.
I feel that it doesn't really matter what they make and, IMHO, it's always been a tipped position just as a waitress is tipped. If I go to a fancy, expensive restaurant, I don't think that I don't have to tip because it was SO expensive to eat there! I still tip accordingly based on service and the total of the bill.
I used to tip $1. a day till I read some posts here. Now we tip $1 per person per day.
Disney Cruise Line gives guidelines for tipping the mousekeeper in your cabin. For the cruises, you tip at the end, though. If I'm going to tip a mousekeeper on a cruise, then I'm definitely going to tip a mousekeeper at my resort as well.
To each his own though. I am surprised though that so many people NEVER have tipped housekeeping at ANY hotel ever. It's quite interesting to see the differences!
PS....I DO NOT TIP TO MAKE A "I have money statement"!!! I tip because I appreciate the service and IMHO it's a thankless, sometimes gross job just like waitressing. I find that comment insulting.