we still don't know what type of hardware will be required to run Oblivion smoothly on a PC but it's probably a fact that a lot of people right now are concerned about that their system might be too slow or lack certain other requirements.
What I thought is that anyone who wants to get some advices could post some informations about his system in this thread - only the main hardware-components, please - and then we could try to help that person with deciding what components need an upgrade - or if a completely new system is needed

"One day before Oblivion is released, you'd better buy the best hardware components available for money..." - Todd Howard