The desolate and ash-blighted road through Ghostgate and up the hill toward Red Mountain, which I first encountered during an ash storm. In the distance, a Corprus Stalker was writhing in agony, holding its head in its hands, while I started to question what my "tender and tasty morsel" of a character was thinking when he decided to take that road. Meanwhile, several cliffracers circled overhead, trying to locate my stealthily advancing form. That creeped me out far more than even the 6th House bases.
The seemingly tranquil but dangerous Grazelands, seen from the hilltop just outside of Tel Vos. Now that I've added MGE to render distant lands and animated grass, I keep meaning to head back there to see how it looks with the extra view distance. Vanilla Morrowind still has a few "scenic moments" in spite of the limited draw distances, ever-present fog, and blocky ground meshes unobscured by the concealing grass that OB uses to "soften" the outlines of its terrain.
In Oblivion, it's got to be a spot on the road to Bruma where it comes close to the edge of a precipice, and the entire Imperial City and surrounding region is laid out far below you. I found myself regretting that my character didn't have a camera. OB's more advanced graphics create plenty of "Oh, Wow!" landscapes, and I considered "sightseeing" to be one of the better aspects of the game, which continued to keep the game tolerable long after I had gotten fed up with the actual gameplay.