Bought Oblivion and a cheap video card last week. My nord is up to level 10, and I'm focusing on the main storyline, although I've done a bit of Blades quests, miscellaneous quests, and dungeon scouring. I just ordered a NVidia 8800GT to replace my cheap card (ATI HD3650 IIRC); I can't wait to see how Oblivion looks with visuals cranked up.
