Oblivion is easily the best sandbox RPG since the 90s, and much better than Morrowind. Of course the writing and VO is crap a lot of the time (although Sean Bean does a good job with the amount of gibberish he has to say) but there's so much of it any other standards would be pretty much impossible. If you want to find flaws with Oblivion you could have a 10 page list after a few hours, but it has so much going for it it's a shame to dismiss it because it can't do everything. Combat is fun and the different perks you earn keep it interesting, the graphics are the best I've seen, quests are surprisingly good especially compared to Morrowind. The scope of the world is impressive, I haven't even been to 3 of the towns yet, I've only closed 1 oblivion gate and I haven't done that many dungeons and I've been playing for almost 40 hours. Overall the best game of the last few years for me, I hope it keeps selling truckloads and a couple of good expansions come out.
And shooting townsfolk with arrows and the knockdown perk is fun.