That's always been one that sounded super cool to me. Honestly I'd turn into weird stuff out of curiosity, like just to see what compound eyes are like, or what it's like to be liquid.
I would like to be able to spread basic education and academic literacy by touch. Like boop - and suddenly your "research" into "liberal agendas" is a joke we can both enjoy.
Would it preserve inertia? Would you accidentally teleport off the Earth? (the earth is always moving on its orbit.) What about air pressure elevation changes?
Ability to know every legal system to the most minute detail. I could then challenge unjust laws, particularly those that are a result of corruption, and have them overturned. It would be amazing. I'd probably be assassinated though. That would be a bummer.
Ability to make your tech into anything like making your smartwatch upgraded to super max with tech not available today. Imagine hundreds of terabytes of storage, ram, super computing in your fingertips. Ability to have tech which can do anything from anywhere. Ability to travel places faster than conventional methods.
Think super sophisticated tech. My first older of business would be creating Artificial Super Intelligence.
The ability to make and manipulate portals. You can travel anywhere nearly instantly. My version of this power assumes you can make the exit portal without physically seeing it. So you could make one at home, one at your work and never deal with traffic. Want to go to London for the weekend? Done.
The cool thing is that you could also bring things to you. Craving a soda? Pop one portal under the coke in your fridge and the other just above your hand. Boom! Gravity pulls the coke through the portal and drops it into your hand. So now you can summon items to you as well.
My version also includes manipulation of your portals. You placed them but can move them while they are active. This allows you to effectively "scan" things. Need to dig a trench? Keep one portal stationary and just pull the other through the dirt. Whatever you scan gets immediately teleported elsewhere.
If we are assuming a world in which superheroes are a thing, you become an absolute badass. Not God like. But you can't be arrested because you'll just leave. You can easily make "rods from God" a reality. You could "scan" a spear fast enough that it's like shooting it from a cannon and impale your enemies. You can use your portals as perfect shields. All attacks would just be directed elsewhere.
I think about this power a lot. To be honest, It's based on Gilgamesh's powers from the Fate anime.
I would want the ability to ask any question and I could see/know the answer instantly. I like to imagine using this on the train to work. I can just think to myself "I wonder how many people Brushed their teeth this morning" and the ones who did would light up. Or, I could ask, "I wonder how many sexual partners each person has had" and their number would appear over their head for only me to see. Good times...
I'd pick being able to time travel, but maybe that's too powerful. So then let's say the ability to time travel but not be able to change anything. I just want to experience other time periods - past and future.