Regarding Macs and reinstall on a new computer, I remember having to
do that one year on my G4, and I freaked, but all was good after. I
think there may have been a hiccup with your district stuff, as Macs
generally run great & for years! I have gone through Macs from the
original "power tower" to the G4's to the newest iMacs--- and the best
buying experience for me has been the Apple store online (& be sure to
get the educator's discount). Better than MacMall, Apple store, or
big box electronic stores....As for storing files, either get a jump
drive with humungous storage, or get an external hard drive (I use the
former for school, the latter for home). Either way, you will always
have back-up in case of an electrical surge, student malfunction, etc.
Usually the HD runs about $200, but that's cheap considering the value
of all your files, apps, and peace of mind.
At our school, my OLD iMac ("the lampshade") still runs great while
the rest of the school (PC based) has gone through 2 sets of PC's in
the teacher's rooms & tech labs; something to share with the school
administrators who are anti-Mac.