If ring of 3 wishes was out of the question, then ring of regeneration seems like an obvious choice.
Since a ring of three wishes is obvious and already mentioned numerous times, I'd go with these.
1. Greater Hat of Disguise Self
a. Assuming it doesn't have the material component
b. Perhaps making it into an armband or something else other than a hat
2. The Jewel of Everlasting Gold
After discussion with an economist, I'd consider devaluing gold or other mundane sources of wealth enough to make them easier to use in more day to day things. Might be especially useful if you can class bars of certain metals that are present in Pathfinder as "Mundane Sources of Wealth".
3. This one's a tossup. Teleportation would be nice, but if we consider nigh infinite money that could be provided by #2, anything short of Interplanetary Travel is less ridiculously awesome. Ring of Sustenance for the reduced sleep would also be nice. Ultimately, I think the only thing that would really make me happy here is 20 wizard levels, so I guess it's ring of three wishes after all. It might take me years to get a properly worded wish to give me what I want, but I'd throw everything I had at it.
