If you are looking to just replace typewriters and overhead projectors in the classroom that is one thing if you want computers to be used to add to educational experience that is a very different goal.
The question comes down to WHY do you need computers in the classroom. Identify your purpose, then your priorities and then an appropriate solution will present itself or at least you will have a much more precise question about which solutions are appropriate.
The most important factor is what is the pedagogical basis for use of computers in the classroom. To effectively implement IT in and educational environment you need a thought out concrete pedagogical justification and a detailed workflow diagramming how your IT infrastructure will operate to satisfy your pedagogy.
I have seen instances where computers provided opportunities that traditional resources did not provide. I have seen faculty use computer based technology to do real time distance learning, adding enrichment material available outside of class time, areas of abstract visualization particularly in math and science, collaborative writing and editing to name a few valuable uses. I have also seen a lot of expensive solutions that were essentially ignored by the students and were utterly ineffective.
In each case a specific purpose was identified, a curriculum was developed to include specific technologies and the role of the computer and the technology was identified in advanced and the tools were selected to match those specific needs and there was complete buy in to the tools by the instructors.
Even though you are not looking at specific applications and are looking at building an infrastructure that can support a broad array of educational implementations, you still need to identify which types of tools are going to be primarily used in your school and build around them to develop an effective solution.
To use computer based technology effectively in the classroom requires faculty educated in how to pedagogically incorporate IT into the curriculum and a administration willing to be purposeful in choices and implementation. Otherwise it tends to be a nightmare of wasted resources and frustration.
