I think it's worth it. It definitely makes gaming more enjoyable; for one thing it lets designers occupy less of the screen with HUD/interface stuff because smaller print is still legible.
I'm less sold on Blu-Ray movies, but that's mainly because my HD set is only 26" and the difference between it (at 1080p) and a DVD (480p-upscaled-to-1080i) is virtually indistinguishable. (And the other advantage BR has, 7.1-channel audio, is lost on my 5.1 receiver.) If you have a bigger screen, though, the higher-density format is probably worth it.
-- Steve