Within an hour, I was completely immersed in Oblivion. So much so, that I began to find myself thinking while laying in bed at night about what I would do in the game the following day. I can honestly say that no game has ever crept into my thoughts on such a consistent basis before.
Graphics are good enough, although I have seen that Skyrim is much better - and seeing the popularity of Skyrim is what led me to take the plunge and purchase the GOTY edition of Oblivion a few weeks ago.
To anyone who has yet to play this game, all I can say is that you've waited long enough, and it's time to give The Elder Scrolls a try.