While the Envy 23 and Envy 20 TouchSmart PCs come with touch screens, SpectreOne and Pavilion 20 are the non-touch screen devices.
SpectreOne is billed as the company's slimmest all-in-one PC as it measures just 11.5 mm in thickness, Mashable reported.
With a 23.6-inch flush glass display and curved back, it features a wireless track pad with multi-touch technology. Users can scroll, swipe and tap through Windows 8 tile-based user interface.
In a press release issued Monday, James Mouton, senior vice president and general manager, Personal Computer Global Business Unit, HP, said: "The clean look of an all-in-one PC and the ease of one-cord set-up are key reasons customers turn to HP. The SpectreOne design is art as well as a powerful entertainment hub. Across our rich line of all-in-ones, we continue to drive value and differentiation that have earned us sales of more than 5 million all-in-ones."
Envy 23 and Envy 20 TouchSmart PCs offer 23- and 20-inch diagonal high-definition (HD) displays. They come equipped with the latest Intel processors, optional ExpressCache and solid state drives (SSDs) and up to 3 terabytes of storage for photos, videos and music.
SpectreOne too features the latest Intel processors, an NVIDIA 1-gigabyte graphics card, optional ExpressCache and optional SSD.
Powered by HP's TouchZone Near Field Communication (NFC) technology, SpectreOne offers a full array of ports, including two USB 2.0 ports, two USB 3.0 ports, HDMI-in and a Beats Audio headphones jack.
While Envy 23 and Envy 20 are expected to be available in the U.S. in October with starting prices of $999 and $799, HP SpectreOne is expected to be available in the U.S. in November at a starting price of $1,299. HP Pavilion 20 is expected to be available in October with a starting price of $449.
HP scrip (NYSE: HPQ) closed flat on Sept.7, at $17.42.