I guess I'm a little weird, but I love to tip. Having worked in the service industry, I know that an unexpected (or unexpectedly large) tip can really make someone's day.
One time, when I was staying at the Waldorf-Astoria in NYC (it was a good rate LOL), I was in my room tending to paperwork when the housekeeper cleaned my room. This was day 3 of my visit, and I'd left a generous tip each day, for which she thanked me profusely. After having witnessed an obviously wealthy couple in the restaurant leaving a $3 tip for a $60 meal (and their service was fine, we were right next to each other and had the same server), I was curious, and asked if getting tips was the standard or the exception. I would have thought in a place like the Waldorf, where I would assume most people could afford to tip decently, it would be the norm. She said it was about 50/50, with the average being $2-3. She also said that it seemed that those people who were the most demanding were the ones least likely to tip.
I am surprised to read here that even with decent tipping, the service has gone down.....my experience has been the opposite, but then, I haven't stayed on property for a while...so I'm interested in seeing what happens on our forth-coming visit.
Regarding tipping amounts, I leave 20% as a standard for meals, and less if the service was truly mediocre and/or awful. For housekeeping, I must confess, it largely depends on my mood/what I have in my wallet. I usually leave a minimum of $5, but have left up to $20 (usually when I leave a note, asking for extra towels/glasses/etc).