Could Dell's decision to offer Linux desktops be enough to push other manufacturers to do the same? It seems that other companies, such as Asustek, may be considering offering pre-installed Linux as an alternative to Windows in desktop machines. It's likely they may only be destined for emerging markets, given that Linux on the desktop hasn't seen stunning success yet:

However, due to the popularity of Windows-based operating systems the Linux-based PCs are unlikely to become mainstream and could be produced mainly for designated emerging markets, said the sources, who also noted that Elitegrup Computer Systems (ECS) had launched Linux-based PCs in 2003 without significant results.
That may change, particularly if Dell's Ubuntu systems are sold in any significant quantity. Most vendors follow what other vendors are doing, if it makes them money. On smaller vendors who often have to pay higher licensing fees to Microsoft, seeing one success story might be all the convincing they need to try it themselves.