I could quote individual bits from pretty much the whole of sleepydogs post, so I'll just say I agree with almost everything said.
I do take into consideration that there are things out of the control of the waitstaff so it would be VERY rare for me to not tip between 10-15% due to sub par service. In cheaper places (like a diner, Denny's IHOP etc) I would usually go more than 15-20% because I think mostly those staff work BLOODY hard for their $5-10 per table. In more expensive places ( like most WDW restaurants) I expect a better level of service. IMHO a guest should get better service if they are paying $100 for a meal than if they are paying $25.
A waiter would have to be incompetent, rude or just plain lazy for me to drop below 10%, although this has happened on occassions. Again like Sleepydog I have found the leaving a few pennies REALLY will get the message home because it shows you actually thought about the tip and were making a point about the service. For a non american leaving no tip doesn't tell the server they weren't up to the job, they just think you're nation are cheap and ignorant (that's not a critisism of Aussies who I think are great, sorry to hear about the cricket loss by 2 runs

) A poor waiter is more likely to blame the customer for not understanding the system than face up to their own short comings. The Brit's in particular, suffer from this, because they tend to suffer in silence and think leaving no tip gets the point across. The best way to send a message to the individual is to leave a VERY small amount of change (one or two pennies) and also say something to the manager. For great service both a good tip and a word to the manager are also a good idea.
I still can't get my head round the tipping aspect for wine though. There is no difference in the job performed in bringing a $20 bottle of wine than a $200 bottle so why should one be worth $3 and the other be worth $30.
On the wider issue of tipping, I do think that the price of food has risen at a faster rate than "average wages" and that the standard tipping amount has also risen. If you go back 20 years it used to be 10-15% was suggested, 10 years ago it was 12.5-15% , 5 years ago 15-17.5% ALL FOR GOOD SERVICE, now those little cards suggest 15-20% and it has become if you leave less than 15% even for average service you're seen as a cheapskate. In a busy mid level to high end restaurant any waiter getting 15-20% is getting GOOD MONEY. I'll accept it's not an easy job, but in an area like Disney where they are waiting 3-4 tables, the turn over is about an hour a table, they are busy all shift and average bill is $100+ the earning potential can easily be $60-80 per hour.
I know there are some waitstaff that work VERY hard and get little financial reward for it, but I'm also sure there are a lot of people that work in popular restaurants that do VERY VERY well out of their occupation. I don't buy into the myth that all waitstaff are poorly paid.