If you're trying to burn a Linux ISO to CD, you can definitely use Toast. I have used toast to burn KDE, as well as several Linux Live cd's (Knoppix, Slackware Live) using Toast 6 and they've all worked out perfectly on my AMD machine.
In Toast 6, you just click the 'Copy' button, and then select image file radio button in the drawer. Drop your ISO on the toast window and click burn. In a few minutes you have Linux on CD.
I think there are a few third party options for disc burning out there, anyone have experience with those? I've found that Apple's bundled software and Toast have met all my needs...
For a while I had to hack Apple's Disc Burning software so that it would recognize my samsung cd-rw. I think iTunes/The-Rest-Of-Disc-Burning supports it natively now so that's nice. Anyone still have unsupported burners at this point?