Hmm. I think what I would wish for would be as follows:
[1] I think I would wish for a very large amount of money... a billion, maybe more. No, I'm not completely geedy but with the ability to invest that kind of money I think I could do some good for those around me. Allow all my friends to not have to work to make a living so they can just work to enjoy themself and do what they want for a career.. that would be nice.
[2] Hmm maybe for my 18 year old male hormones to be a little calmer than they currently are, I think that would be a pretty nice change at this point in time. (don't ask..)
[3] I think I would wish for telepathy, the ability to read minds. I think that would be a very easy way to know what the people around me really want. It would make decisions affecting other people much easier to make and would possbily prevent further conflicts. Plus, I think knowing other people's deep dark thoughts would be very interesting
-- The reason I didn't say immortality would be because always seeing those you care about die and you living on forever doesn't really sound that great to me. If I was to wish for immortality, I would have to wish for someone else to be immortal as well, and I'm not sure if that person would be up for it, for the same reason.