I've heard of the 2.6.8++ issues,
I'm running 2.6.9-1-k7 and have only minor probs with both cdrw or dvdrw drive.
CPU usage during burn has reduced dramatically since about 2.6.6(?),
DVD+R(W) burning at whatever the system can handle, even with only a Duron 750,
or burning from an old raid 5 Proliant 2500 server (dual ppro) which only dishes out about 2MB/s.
Haven't tried audio cd's though (no use for them