Thankfully I don't have to deal with delivery fees in NYC. I'm usually around the 15-20% mark for delivery but if i got something small i wouldn't tip under $2. A pizza is around 12-15 so I'd generally tip around $3 for about a 5 block or less walk. I also use seamless web to order thus pay by cc so I don't have to worry about change or rounding.
Hoke was top notch at this aspect of his job.