Everybody has such incredibly high standards and expectations for a game like this, and they are rarely fulfilled or shift elusively at the game's release. Some people want it to be just like another game. Some people want it to bear no resemblence to any other games. Some people nit pick things which have very little bearing on the gameplay like the color scheme and the engine's flexibility (which in all honesty I doubt that you have any crediblity whatsoever to be critiqueing the technical aspects of Doom3's graphics engine). Other people hate it because it's popular, other people try and compare it to other games that aren't even out yet. It is my humble opinion that most of these people either did not bother to read what the game was about before buying it, or sucked horribly at it.
In light of all of these negative threads about the game, here are a few things that I liked about it:
Controls & learning curve: Very simple. Don't need 34 buttons for interaction when 7 or 8 will suffice. I don't like FPS games that have a high learning curve and lots of buttons, it detracts from the story and pulls your out of the game.
Graphics: The graphics in this game surpass anything I've seen so far, even Farcry, but what impressed me most, unlike far cry, was that this game looks amazing even at low res and lower detail levels. Textures are low contrast so as to make AA almost entirely unnecessary.
Plays very smooth on my modest computer and looks amazing on my 33" monitor at 800x600, high, all adv. on.
Sound: Best since the original Half-Life, IMHO. Very creepy, very immersive. I'm playing on the 5.1 setup through my home theater, and the intensity of the sound with regard to position and distance feels right. Echoes sound right. Very scary, easy to lose yourself in the ambience of a room. The sub hits nice and hard when an imp hurls a fireball a little too close. Things whiz by your head and it sounds realistic.
The demons are very creepy and their movement is more fluid than I've seen in any other game. They blend perfectly with the environment, and it gives a very movie feel. The humor is savvy (the space spam for instance) and adds to the not so distant future feel of the game. They also kept a lot of ties to the original games, like the dark, claustrophobic feel and the morbid, undead texture to some of the areas.
I could pull the elitist schtick like so many of the other players on here, but I'll be honest and not say "the game isn't scary at all, it's stupid". The game is creepy, in numerous ways. There is plenty of the loud sudden surprise make you jump stuff, and then there is the slightly more subtle but ever present tinges of evil; grunts, scratches, gurgles, darkness, red vision, disturbing gory cinematics, scenes of hell bent wickedness, demonic murmers, etc.
I probably don't play video games as much as the rest of you. I work my 40 hours a week, don't live in my parents' basement, and my fiancee battles the computer for my time and usually wins. Still, I played the first Doom games a decade ago and enjoyed them to no end, and while I was not expecting much substance with Doom 3 partially because of the hype and partially because of all the effort the graphics engine must have taken, I was pleasantly surprised to find this game an attention holding, immersive, tense, and satisfying experience thus far.