The market for all in one PCs saw a 57 percent growth between 2008 and 2009 and is set to show further growth during this year.

That's according to market research company Displaysearch, in a report that indicates growth rates in this market will be comparable to those of notebook PCs.

Chris Connery, VP of Displaysearch's PC division, noted that all-in-one units have been around for years, most noticeably for the Apple iMac. "Historically, they have been benchmarked against the traditional desktop PC and monitor bundle, but they are becoming a market of their own with each consecutive generation," he said.

All in One PCs market share
All in one desktop sales by manufacturers - Displaysearch

And they're appealing not only to home users and enterprise users, spurred by more attractive designs and cheaper processors.

Displaysearch says there's a market split on touch screens as an interface for the category.

"Most see touch as a nice alternative interface for stationary or larger size personal computer products but not as a substitute for the tried-and-true keyboard mouse," he said.

Many vendors added touch to products last year in an attempt to up sell, and HP is planning to make this functionality a long term feature.

Apple, however, doesn't offer touch screen versions and the share of such machines worldwide was 22.4 percent in the fourth quarter of 2009. Windows machines showed a 37.7 percent penetration.

Growth rates for both touch and non touch all in one systems will lag behind only the fastest growing mini note/tablet PC category, Displaysearch thinks.

All in One
All in one desktop PC forecast - Displaysearch

Compound annual growth rates for all in one desktop PCs will be 13 percent; for mini-note/slate PCs 14 percent; and for notebook PCs 17 percent, Displaysearch estimates.