I tip pretty high from a percentage standpoint, especially somewhere like Denny's or IHOP. I have always found it strange that a tip is based on the amount of the bill as though those at expensive restaurants work harder.
I repsect that someone is doing a tough job to support themselves rather than be on the dole. Although I am not rich, I am comfortable enough to know that the server will appreciate and use the extra few dollars far more than me and by next week I will not know the difference or miss the money in any way.