Living In Oblivion
"Unless you have a high-end rig, you're probably going to want to go with the 360 version."
I disagree...you overlooked one of the greatest parts of the Oblivion experience...the mods. These are user created changes to the game that enhance, alter, add to, or "fix" the game as it came out of the box.
Already there are over 100 mods available that do things from altering the leveling of the npcs, adding battles to the arena, and changing the UI to be less "console'ish"
That is one of the great reasons for going for the PC. The 360 will only have official patches or updates and will miss out on this entire wonderful area of the game.