For me, Waveburner Pro from Emagic was the best CD mastering program ever. I really missed it when Apple bought them and never released an OSX version of Waveburner. I recently bought Logic 8, JUST TO GET WAVEBURNER. I was not disappointed. The interface, compatibility with plug-ins, etc have all improved. I love it. I got a good deal, %500 for Logic 8, which is a lot to spend just for Waveburner, but it was worth it to me.
Before Logic 8 came out, I actually brought my old Mac 9600 out of mothballs, hooked up all the old SCSI drives and got it running, just to use Waveburner Pro in OS9 when I had a demanding project. It still worked like a charm. Soon thereafter, Logic 8 came out and I snapped it up. One of these days I'll have to learn how to use Logic. I'm a Pro Tools guy, but Logic looks really cool. I was shocked at the time it took to install Logic though. I did it over 3 days. I think it must have taken about 18 actual hours of installing. WOW.