I'd say move with the times. A school network shouldn't be restricted to running any particular system.
Get your infrastructure sorted so that you can take any apple/android/linux device - it's all possible given the right level of investment. Eventually you can save money and open the school up to a different style of learning. It's not an argument about macs vs pc's. it's an argument about interoperability, sticking with the old school corporate domain based windows systems restricts the possibilities.
this was pretty much my checklist:
1) solid network
2) DMZ for 'public' applications
3) VLE
4) Citrix to allow win apps on ipads/osx/android/linux/bsd etc
5) cloud based document and email system (google docs)
6) decent authenticating proxy (smoothwall)
7) Decent wireless with 'public' vlan
8) get a decent broadband provider with 100% SLA and failover
With this in place you should be able to cope with any type of device
SLT throw at you