When you say "just started Oblivion" if you mean this is your actual first time in playing it your best bet is to give it a play through with official patches only and work out your like and dislikes, what you want changed and what you don't want changed, what you would like to improve and so on an so forth.
Adding mods straight off the bat will put you in a position where you are unable to fully appreciate what it is the mod does because you would have no idea what it was like before it was changed. So IMO give it a play through first and then come back because there are THOUSANDS of mods to choose from and you will have more of an idea on what it is your looking for

If you have played it just discard what I said and wait for people with their options ans opinions