HP has unveiled plans to ship PCs that can both read and write to Blu-ray, and can read HD DVD discs.

The PCs use LG's Super Multi Blue Blu-ray Disc Rewriter and HD DVD-ROM Drive (model GGW-H10N).

The LG Super Multi Blue drive is a triple-format writer. It handles writing to Blu-ray Discs at 2x (single-layer and double-layer), as well as to DVD and CD.

The only reason that the drive can't write to HD DVD, is because there is no HD DVD writer currently shipping for desktop PCs yet.
HP are installing the drive into its Media Center lines, the m8010y and the d4890y.

So far there is no news on pricing.  It seems that all models will have HDMI output, and an nVidia-based GeForce 8000-series graphics card that's HDCP compliant.

HP expects to make the drive available in 4 to 6 weeks.

More here.