Just last week, we got a peek at Nvidia’s new line of HD-video-playing processors in downtown Manhattan. One, the Ion, is a GPU that pairs with an Atom processor to give Netbooks gaming and HD-video-playing muscle, coming soon in Netbooks from Lenovo and Samsung.

The other, Tegra, is an all-in-one chip: it has an HD video processor, but it also has an ARM processor, making it an all-in-one computer on a chip that will be put on phone company-branded Netbooks toward the end of the year, according to an Nvidia representative.

But that’s not all, it seems: rumors around the Web are suggesting that the Tegra might be placed in upcoming smartphones as well. With a Tegra processor, these phones would have pretty impressive HD and gaming capabilities.

Add to this Dell’s entrance into the handheld Internet device arena and the beefed-up graphics of the iPhone 3GS, and an interesting showdown is in the works between the new-generation smartphones and fall’s upcoming crop of graphically superior Netbooks.

Assuming prices hold steady, the costs might be similar, too. A Netbook can currently run between $299 and $500, while smartphones run between $199 and $299, subsidized (and up to $600 unsubsidized).

There are even some new ‘tweeners…