Does anybody know when the next update to Logic X might be due. I am primarily an acoustic musician, and at the moment I cannot see too many advantages over Logic 9.

Apple very rarely give info to end users on their release schedule. Logic X is great and has lots of improvements over 9. Track Stacks, Flex Pitch and Smart Controls being just 3. However, if you're happy with version 9 and are making music you're happy with then there's no harm in staying put for the time being :)