Invisibility - so I could go anywhere I wanted to pursue my interests without being seen, and also so that no-one could look at me unless I wanted them to.
Also I'd love to have Hermione's "time-turner" from Harry Potter - so I could do all the things I want to even when they are all happening at the same time - and so that I need never be late for anything again!
Then of course I'd need immortality, otherwise by doing the above, I'd halve my apparent lifespan!! !! !