I love the Mac OS for so many reasons, but the personal finance software options blow. Google the right keywords and you'll get pages and pages of people lamenting the pitiful state of this type of software on the Mac, and begging for people to come up with solutions. They still haven't.
There's Moneydance, Cha-Ching, Quicken, iBank, and a few other minor apps. Practically none of them have the tight integration with online bank accounts that Quicken for Windows and MS Money do; most of them are cute personal budget-type apps rather than being one-stop money management apps.
Personally, I use Quicken 2007, but it doesn't keep tabs on my UK and German accounts, and I have to manually download most of my US transactions instead of just a one-click automatic update.
I wish I could point you in the right direction, but sadly, I don't think there's a right direction to go in. As "swiftaw" said, Parallels and MS Money might be not just your best option but your only option. And I'll join the chorus of lamenters: we need good personal finance software for the Mac. Desperately.