I've done a bit of this stuff ( computer based recording and instrumentataion ) along with researching it and have used a Celeron, P3, P43 and AMD in the past ( and an Atari in the "way" past.

I absolutely agree with Gary. If you're going to use it as a machine to play / record midifiles or even for playback of audio files, it should be fine.

I would not recommend a Celeron if you are planning to use Vsti's or do some intricate work in a more complex DAW like Cubase or Sonar.

Most pro audio sites will echo what we've said here btw.

AJ