Most education customers already have licences to run Windows 8 (either through an existing academic subscription like EES, a School Agreement or a Campus Agreement; or through MSDN/DreamSpark), so if you've not given it a go yet, I'd recommend installing it on a spare laptop or desktop computer. That way you can have a play around with it, and also try out some of the new apps, in advance of the big launch day on 26th October.
My personal Windows 8 education app favourites that I'm playing with at the moment are:
Windows Store link for Wikipedia
It's the usual great content from Wikipedia, but with a smart new interface, and especially useful semantic zoom
Windows Store link for Physamajig
A great teaching tool which really takes advantage of a touch screen
Windows Store link for Mind8
Simple mind-mapping, which would really useful to help students prepare revision or for assignments
Windows Store link for Wordament
My favourite word game
Windows Store link for the Periodic Table app
This does exactly what it says in the name!
How Stuff Works
Windows Store link for How Stuff Works app
A great app for curious minds, which always takes me off in a completely new direction every time I load it
I'm going to try and find some time to share some deeper reviews of the education apps (now, where is that extra 25th hour in the day?), but hopefully there's enough pointers here for you go off and experiment with the new Windows 8 education software.