Large but bland
Oblivion is huge, both in terms of the game world and the number of quests involved. Its visually stunning and, despite problems on some systems, managed to run more or less flawlessly on my fairly mediocre system. The greatly non-linear game-play removes the strict need to do X, Y then Z, and theoretically allows many hours of game-play without even touching the main plot.
But the sad thing is that the game ultimately lacks character. The visuals, although stunning are ultimately repetitive, and the quests themselves are similar. Cardboard cutout characters speak the same lines and have the same reactions, none of them able to endear themselves. The main plot and the sub-plots are uninspiring and generic, with the majority of the quests boiling down to the same basic game-play.
The game also fails to show progression. Enemies level with the player, and yet only end up getting bigger and stronger, and don't offer up anything fundamentally new. Meanwhile their constant levelling means that although its possible to change your play-style at any time, this leaves the main character critically underpowered.
At first I left the main quest largely alone, and explored the world, completing various sub-quests. Yet I soon realised that there was little actually there, and the first five minutes were pretty similar to the last, and after many hours of game-play I hadn't actually achieved anything.
The Bottom Line
Impressive in scale, but ultimately of limited character. The repetitive nature of game-play soon begins to grind, and the game never delivers a major feeling of progression. The strong modding community may be able to instill a bit of variety into the game, but by the time it had taken off I had already tired.