Turok was a very nice game. Probably underrated, but not by much.
There are still many much better FPS on the HD consoles.
Some other underrated games:
Too Human, Saints Row 2, Assassin's Creed, Ninja Blade, GRID, MagnaCarta 2, Resistance 2, Viking, Lost: Via Domus, Lost Planet
Most of them also not by much, but all of them deserve at least 5 more points on a 100 scale (searched via Metacritic)