First of all, I have used many applications in the classroom including: Strata 3D, Cinema 4D, 3Ds Max, and Maya. To be fair, my strength and training has been in Maya and that is the direction I leaned.
I bought 3ds Max for my middle school classroom first. It was one of the cheaper applications out there and there were tons of resources. I wanted to go the Maya direction at the time since that was my strength, but it was a bit pricey. The following year when it came to update, Alias released a PLE version (Personal Learning Edition) which allowed my students to practice at home. ALSO the price of Maya dropped significantly. This was a tipping point for Maya both in my classroom and in industry; it seemed that everyone started using it and resources were available everywhere.
In my high school classroom, we use Maya. It is one of the top applications in industry and majority of the schools, colleges, and universities are using AND is what a large percent of industry is using.
As far as I know, schools are using either Maya, 3DS Max, or Cinema 4D. Personally, I don’t know why schools would even bother with Cinema 4D. There are minimal resources available compared to Maya and Max, only a small part of industry is using it (A few television broadcasting groups), it is a little more limited then the other two, and The price is really comparable.
Autodesk Maya Complete 2008 Student SLM (Perpetual) - $299.98
Autodesk Maya Complete 2008 Student SLM (14 Month) - $149.98
Autodesk 3ds Max 2009 Student Version (13 Month) - $99.98
Maxon CINEMA 4D R10 - Win (Enrolled in a CG Course) - $195.00
Newtek's Lightwave
Softimage XSI
Houdini
NOTE: Need to talk about Blender . .
Also here is a great forum about choosing the right 3D Application on 3DBuzz.com
http://3dbuzz.com/vbforum/showthread.php?t=128803
