Metric. It makes more sense for animals used to sets of ten.
The times I don't use it are usually mathematical... cause then we're using radians instead of gradians, mostly because of all the magic to do with sin and the unit circle. Also, Pi is better than Tau, no matter what you say.
I don't like imperial, it makes no sense, and it doesn't factor well when being dealt with mathematically. Being able to use prefixes like kilo, mega, giga, micro, nano, etc, across weights, distances, speeds, accelerations, hard disk sizes, tons of tnt equivalent, force, and so on gives a great sense of scale. There is no reason to use wildly different, and illogical, measuring systems for other things. We have ten fingers, our numbering system is decimal, and therefore, our measuring systems should be decimal too.
Oh, also, I don't know what an australian tablespoon is, but I always learnt it as three teaspoons. (~=15mL)
Edited by Redezra, 19 November 2014 - 06:25 PM.