<<I wish I were (traditional usage)
I wish I was (modern usage) >>
Both work for me, though the first is more formal and probably a little more likely to occur. I have different preferences for different persons though: I think I would more likely say "I wish it was" than "I wish it were". He and she can go either way.
I wish I was (modern usage) >>
Both work for me, though the first is more formal and probably a little more likely to occur. I have different preferences for different persons though: I think I would more likely say "I wish it was" than "I wish it were". He and she can go either way.