I designed the MMB103 that I am using for my controller board to have an Atmel-standard 6-pin ISP header as well as a PonyProg serial interface. I had been using the PonyProg interface with its software on a Win32 system for years. I lived with the 7 minute programming time (for 128 KiB Flash on the ATmega103). Even after I switched to a PowerBook in 2003, I would always borrow my wife's Dell to burn my chips.
Well, I finally got fed up with the long waits to test my code. I got an STK500 from Digikey. I got the package deal where the STK500 comes with the JTAG ICE MkII. I connected my Mac to the STK500 via a USB-to-serial adapter. I set "AVRDUDE_PORT = /dev/tty.KeySerial1" in my Makefile. I typed "make program" and BOOM! My programming time went from 7 minutes to less than 20 seconds.
This is SUCH an improvement in quality-of-robot- programming- life that it was well worth the money. Next I intend to find something smaller than the STK500 so it is portable. Hopefully I can also find something that is all-in-one, so I don't have to use a USB-to-serial converter and can use power from the USB port.