Then see my point about the UK/metric/Imperial. ;-)
Incidentally, in that link there's a very common example of bad usage namely the volt/voltage. 120V is shown as bad usage and 120 V good. One sees the former usage on machines, appliances, in printed material etc. so often that it's almost a de facto standard.
I'm inconsistent in my use too, one time I'll include the space at other times not.
I love this, thanks so much for writing it! I'm writing a blog post on metrication and this will be a super-useful resource for the sort of pedantry I intend to engage in.