Sega is guilty of not caring after its favorite son, Sonic. In fact the best game with Sonic in it in the last 5 years is probably Super Smash Bros Brawl, made by Nintendo.
The above video is not officially released by Sega, but accompanies the alleged Sonic Unleashed screenshots. It looks official enough to me, probably just waiting to be revealed at a press conference or by a magazine/site exclusive.
Whatever Sonic Unleashed is, it needs to be good. The GameBoy Advance and DS Sonic games have done well rehashing classic Genesis gameplay, but do little to advance the franchise. Sonic Unleashed is supposedly for Xbox 360 and PS3 and could be somewhat similar to last year’s Wii Sonic game (which wasn’t met with great reception, but wasn’t really bad either)