...Although I've heard this said many times in my life, I've never really understood it. No matter how beautifully a cake is decorated, the point of a cake is to be eaten. Now that I've played The Elder Scrolls IV: Oblivion, I think I understand. Only, with Oblivion, as soon as I was done uttering that statement, I would proceed to grab a fistful with my hand and shove it in my mouth and then just start playing with the cake.
The visuals in Oblivion are nothing short of amazing. The water effects look like something out of a technology demo, with realistic reflections and interactive waves. Breathtaking.
The models are extremely detailed and are well done, right down to the facial animation. The one thing about the faces in Oblivion that I highly applaud, but it seems to be (ever-so-slightly) off the mark, is the aging of characters. You can choose the apparent age of your character, which will change things such as coloring and amount of wrinkles, depending in part on race. The part that seems slightly off is the wrinkles. I can't put my finger on exactly what is off, but I think it benefits from this addition to the depth of character animation. You get a good feel for the age of NPCs - the characters are just that - characters. The highly detailed character animation and models combine with the excellent writing to create believable characters that make you feel like part of a story, rather than a casual observer who's waiting for the text to end so you can kill something else.
The musical scores in The Elder Scrolls IV: Oblivion are well done and fit the action and environments very well. Most of the time, they just sort of add an ambience to the game, but at times the change between different pieces will be a bit abrupt - typically, however, this occurs when you enter (or leave) a city or other large area; basically, the environment is changing and the music follows its lead. The sound effects do a good job of reinforcing the environment that you are exploring, as does the large amount of voicework. Oblivion is very well "put together," from a production standpoint.