Just buy retail edition on PC, cheapest and will be better than PS3.
Also FWIW I didn't feel the game needed mods (although that's not to say there won't be some very good ones that did improve things).
I'm inclined to agree: my experience of mods for bothFallout3 and Oblivion is that they tend to fall into these categories:
1) Make the game much harder. Great if you are experienced, but I've never seen why experienced players feel the need to recommend these sorts of mods to newbies
2) "Improve" the look. Some do, some don't; and even the ones that do screw up here and there. They nearly always have a massive performance penalty as well, so you need to wait until the game is years old before your hardware can run them.
3) Add loads of extra weapons and armour, mostly massively overpowered or stolen from other games/films/books. That said, I did try to to make Nethack mod for Morrrowind.
4) Add a house/den etc, usually with way too many features (training areas, buffs to stuff and skills etc). My first mods to games are usually houses, so I understand the idea, but mine are fairly simple and are intended mostly as storage.
While mods change a game, neither Oblivion nor Fallout3 is broken enough to "need" mods, unlike (say) Gothic 3. There is probably no such thing as a "must-have" mod for either, and my advice for newbies remains the same for both games: play it vanilla, decide what you don't like, then get a mod which changes it. Ignore the siren call for this and that "essential" mod, because there's no such thing. There's a vast gulf between you liking it and it being essential.
M