I have a scheme where all our teaching staff have a laptop. We did look at all classrooms having a dedicated PC...but at a time where the school was being rebuilt and we didn't know how many rooms there would be, and remote access was next to non existant - we went with laptops. The laptops have a 4 year warranty and are part of a pool, which rotates round all the staff as we need to recal for maintenance or repairs. Most repairs are for HDDs, we've had the odd expensive screen but they are rare. No matter which way you go...you have a commitment in costs.... Classroom PC and good home access for planning; or laptops.