Starting from scratch ... MSFT, OpenOffice, or something else?

I have a start-up private school that heavily uses CBT, approx 70 students, but will be expanding into multiple campuses rather quickly. Basically the staff uses paper files, spreadsheets, and lots of email all on personal laptops. (Most of them are Mac)

So now it is time for them to pull the trigger and do it right. Email and web hosting is outsourced. They need everything from backup to scheduling, office automation, databases, everything one would expect.

I have already made a decision on smoothwall's firewall/content filtering & for a firewall to separate the students from the office intranet that I will set up.

So now it comes down to the philosophical question ...
Pay the Microsoft tax and go with office, sharepoint, and all the other content management, or use OpenOffice as a foundation (with Intel-based Solaris) , or something else?

Suggestions? I want to learn from all of the coulda' shoulda's and build the right foundation from the start.

P.S. I haven't picked the hardware, but have been a storage/RAID architect for 20 years, so no headaches or questions concerning backup/availability/reliability. I will be using VMWare to virtualize the Smoothwall software, as well as any other machines necessary to get these guys into the 21st century.

another plus for google apps - we are using it here for admin and the IT dept are starting to teach with it. Although google docs lacks some of the features of OpenOffice it is great for 99% of things and the collaboration aspect and integration with google sites is fantastic

Well, first it is a for-profit school, so I already contacted Google to ask what pricing would be. The site says it is free to non-profits, at one place, and found another link that just said it was free to schools.

In any event, even if they had to pay same as any other kind of business, the price is right and this eliminates some headaches. No issues with internet bandwidth either.

So google apps is something I will check out for sure, and it could very well be at the top of the list in a few days.

i tend to blanket deploy open office so all pcs have something to sue then deploy ms office as required