SPECIALIZED REPLY:
If you are burning a CD-R for audio mastering purposes (there are very few people in this boat, namely musicians) and want the absolute lowest BLER rates (assuming you are using good media - which is getting hard to find), then Plextor is king of the hill.
I am not talking about throughput or price, merely consistency and lowest amount of errors.
Cheaper Lite-on CD-R drives, which are commonly remarketed (I own three of them) good everyday machines but have a tendency to build up more errors 2/3rd's of the way into a red book audio disc. Most of the time this does not cause an audible / tracking problem on a 1st generation. It's nothing you want to replicate or send to a pressing plant though.
The Pioneer 107 drive is excellent if you are looking at the highest quality "well-rounded" drive. I give the Plextor the nod for CD-R audio mastering type purposes.