would it be worth playing it on the pc ive already played heaps of it on the 360. but im thinking about playing it again on pc, (im on vista so consoles dont work) ive just seen heaps of good mods

Yes. It is quite easy to accumulate hundreds, if not thousands of mods to enhance your game play experience. Once you've done most of what is offered via Vanilla Oblivion, it's time to experience the other side with lots and lots of mods. You can literally make the game look entirely different just through graphics mods, and then after that it's not hard to add dozens of new enemies, new rules to the old enemies, dozens if not hundreds of new dungeons/ayleid ruins(I myself am a fan of the Ayleid ruins, so I have like 30 or 40 mods specifically devoted to them), and of course, hundreds upon hundreds of new quests. Hell, some mods(very large ones) even add new landmasses to explore I do believe. I highly recommend buying Oblivion GOTY for the PC and going on a download spree. Perhaps first asking on the Oblivion Mod forums for good recommendations(though I do advise you give them a good idea of the kind of stuff you like so they can suggest appropriate mods)

If you already have a PC capable of running the game then yes, it would be well worth playing the game again on PC. There's a bunch of mods for Oblivion and you could also play the http://www.nehrim.de/indexEV.html.

Yes, buy it. I have Vista and overcome the console problem by having the Ring of Console mod which requires OBSE. I can't find a link at the moment, but its worth downloading, if you only get one.

Well worth it, you can fool yourself into thinking you're playing a different game with all the mods available. Even if you still want to play a mostly vanilla game, you can get all sorts of graphical/UI enhancements and bug fixes.

Playing on Vista doesn't automatically mean you can't get to the console. I believe it's only the media center edition that causes trouble. I run plain 64 bit Vista Home Premium, and can access the console just fine.

I would say, when it comes to Bethesda games, if you have a PC capable of playing the game smoothly, you'd be doing yourself a disservice by playing it on X-Box 360 or PS3 instead. As others have said, even if you DON'T want mods, you'll get better graphics. And then you'll always have the possibility for mods.

The only thing X-Box 360 has over PC is achievements.

And those are a matter of taste. I prefer my games free of that nonsense.