World of Warcraft(WOW) is a massive multiplayer online role-playing game(MMORPG). It's kind of like an online community almost, which means that it takes place strictly online and it costs cash to play online.
Elder Scrolls IV: Oblivion, is a computer game that does not take place online and it is awesome. I have Oblivion for the XBOX 360 and I love it. There is sooo many things to do and see in the game, that it never truly ends and I think that is sweet.
I don't know about the Battlefield games, but I do have Call of Duty 2 for the XBOX 360 and that one has it's own game that you can play through offline, but I mainly play it online, I suck really bad, but I like to play with other people it's pretty fun. I think that the Battlefield games are similar to the Call of Duty ones.
Here are some links for further reading:
http://en.wikipedia.org/wiki/World_of_warcraft
http://en.wikipedia.org/wiki/The_Elder_Scrolls_IV:_Oblivion
http://en.wikipedia.org/wiki/Battlefield_%28video_game_series%29
http://en.wikipedia.org/wiki/Call_of_duty
Hope this helps.