This depends a lot on the industry. A lot of the "creative" industries actually use or prefer Macs. This is especially true in graphic arts and some of the video editing fields since this is one area where Macs truly stand out. Having a fully integrated and unified color handling system is literally priceless in these areas. A lot of scientific and engineering work is moving to the Mac (from UNIX) since the move is relatively painless (UNIX lurks under the hood of OS X). On the other hand if they need business utilities, including many business focused web applications they may really need a Windows PC. DirectX and some of the other MS only things make many network applications fully dependent on Windows.

- Eric