The last time we weighed in on the HP Pavilion HDX, we crowned it one of the best notebooks of 2007. Today, HP released two follow-ups to the HDX, but they take an unexpected form. Whereas the original HDX had a 20-inch dual-hinge screen, and was really only a laptop in name, the HDX 16 and HDX 18 are clamshells, and they’re actually portable. As the names suggest, the 16 has a 16-inch screen, and the 18, an 18-inch. Both are stunning, 1920 x 1080 displays with 16:9 aspect ratios, which make the screen wider– but not much taller– than your traditional 15 or 17-inch notebook. They look kind of like the recently revamped DV series, only with a different pattern and more subtly integrated speakers. Both have Altec Lansing speakers, subwoofers, Blu-ray drives, and sleek, flat bezels. Like the original HDX, they have internal TV tuners. The HDX 16 starts at $1,299 and the HDX 18 at $1,549. Other specs: they run on Intel Centrino 2 CPUs, NVIDIA discrete graphics, Intel 802.11n Wi-Fi, and can take up to 8GB of RAM. The HDX 16 offers hard drives as large as 350GB, whereas the HDX 18 will be available with dual 7,200 rpm 250GB hard drives. Check out our hands-on video and photo gallery below or visit our full review of the HDX 16. Stay tuned for our HDX 18 review later in the week.