I use Soundforge on my Mac under VMfusion4 and its perfect.
So if you already own Soundforge , you can buy VM Fusion for about $40
You can run it in a window so it looks just like a mac program, you can pass data to and from it.
I tried Peak and I unreservedly hated it. (In fact I'm selling my copy in the SOS reader's Adverts)
Audacity is OK too but lacks the bells and whistles.
Hope this helps