I don't know. With IBM buying 200,000 Macs, like they anounced recently, it's possible that other companies will follow. Many of the largest companies in the world are old and conservative ventures, they don't like taking chances. Those companies are likelly IBM costumers in some form or the other, with Big Blue going to Apple, their costumers might feel secure enough to change themselves.
I can see Apple growing strong on the enterprise market in the next few years.