Phantasy Star Online, the company has been rather steadily turning out new titles bearing the brand name. Most recently, it's been Phantasy Star Portable 2 for PSP, but, as discovered by Siliconera, Sega has at least two more Phantasies planned.
The Japanese Trademark Database lists both Phantasy Star Eternal Planets and Phantasy Star Eternal Hunters as recently registered. They're classified only as video games -- no platforms, natch -- and Siliconera speculates they could be two sides of the same coin ... er, game, a la Pokemon Black and White. Hopefully, Sega won't keep its phans waiting long for a reveal.