I am really an open source person - but my district has been Windows K-12 except for iBooks (furnished by the state) in grades 7-8. Now we are being issued MacBooks to every HS teacher. I am here to listen to you to help my (our transition). We will be running parallels since there are no other Macs in the building.
Wow! I am really jealous. It sounds like your district gets it. Macs are the way to go for a multitude of reasons. They are a powerful machines and do not hold a candle to PC. I remember when I started teaching, there was a MAC lab with old Apple 2s- Mac has come a long way!
I love the mac's that makes up about 95 percent of the machines in our district. Window make up the other 5 percent and 1/2 of that is the network equipment. We have kids doing garageband, imovie, ichat etc. with in the network. You can not beat the built in applications on a mac.
Like many of the other comments, I really enjoy using my MacBook and the programs that have been listed. Perhaps one of the best things (in my opinion) is how well the programs work together.
I use both Macintosh and Windows machines. It is possible, and for those who need the Windows OS, a great option to run both platforms on the MacBook.
I have used Parallels with great success. My windows friends have been excited to see what can be done in sharing between operating system platforms.
I have had several friends who transitioned to the MacBook at their schools. As I have helped them in the transition process, I found there are some ways to make it easier. Perhaps one of the easiest methods to help in the transition is to utilize the various "Macintosh" podcasts. I show my friends (many who have never listened to or viewed podcasts) how to search for and download podcasts using iTunes. My recommended podcasts to these friends have been "Apple Quick Tip of the Week" "MacBook Podcast" "ScreenCastsOnline: Mac Video Tutorials (FB)"