I’ve gotten Doom 3 last week on Monday and have played it quite a bit (but I am nowhere near finished) and it looks very nice and it has made me jump more often than I care to remember.
Unfortunately, it is very CPU limited. Whether I play it at 640×480 or 1280×1024 on my Radeon 9800XT makes no differences whatsoever as my (dual) Athlon 1800+ cannot keep up with skinning and shadow volume extraction.