In truth, there is no one person I would want to switch lives with to have their life. I want to have my own life, but I wish I could push the fast forward button. I would love to switch lives in the concept of accomplishments. I would love to switch accomplishments with someone who is done with their education up to their masters degree and has a job that they love. Other than that, I don't want someone else's spouse, bills, children, house, and so on. I want all of that stuff on my own... But I just want to be done with school, and have a job I love passionately.
I would switch for that level of accomplishment, but nothing else.
As for one day? I wouldn't want to switch days with anyone, really. I like being me alright. :)