Agree - Mac version is needed
I'm in the same boat. I used to use the free web version, then Purchased Fitday 1. I started using Macs 7 years ago, and continue to use Fitday only because I have XP on VMWare for work on my mac.
It's difficult on the go to enter what one is eating, even when cooking in the Kitchen, having to go back to Fitday often to enter details.
The Killer Combo for me would be a native Mac version which Syncs to an iPhone/iPod Touch version of the application.
I've held off on the upgrade to V2 of Fitday as it's JAPCA - Just another PC Application :-) and Fitday 1 meets my needs for now.
If/When a Mac version hits the site - I'll happily pay upwards of $50 for a Mac/iPhone combination of the application.