Generally as small as possible - but there are a ton of considerations, what its for, is it being used in conjunction with other music, what is the format it's playing on..etc, etc, etc.
Generally I would say about 80 - 120 Kb coz that would allow a 10 second loop or something so that it doesn't get really annnoying looping every 2 seconds.
Cheers
Jesse
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Cheers
Jesse Stratford ActionScript.org Cofounder
Please don't email or PM me Flash questions, that's what the Forums are for!
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