IDC is predicting that:

“Portable PCs will represent more than 50% of all Client PCs worldwide in 2011″

It’s difficult to deduce from the report, but I assume that most of this transition will be driven by consumers rather than corporate purchasers. While enterprises are becoming more mobile, everyone I know is buying a portable device for their home. A portable device and a wireless LAN at home gives far more flexible access to the Internet which is the primary reason people seem to have a PC. The exception to this are the high-end gamers who still need a desktop for the graphics performance.

I’m sure I’ve heard these predictions before, though, and I’m not sure they are true this time either.