A couple have mentioned some variation on “stop accidents”…
How many accidents do you actually encounter, ones that you’d be aware of at least an instant before they happen? Remember, we can’t reverse time, here, just stop it and start it back up again. Do you plan to constantly run through stopped time, looking for crises to avert?
Heh, this was pretty much the thought that occurred to me numerous times when I was in school. Stopping time just to be able to spend more of it sleeping would have been at the top of my list of “superpowers I wish I had.”
But then, of course, I’d start thinking about the physics of it. Seeing things would be pretty difficult. Even if I occupied a small bubble in which time proceeded as per usual, no light would enter the bubble from the outside. Similarly, no electricity or ethernet signals, so browsing the 'net is right out. I’d have to bring a laptop and spare batteries if I wanted to get any work done, or else rely on a flashlight and a pencil and paper. :o
And what about the forces on objects crossing the boundary of the time bubble? I imagine some strange things would happen at the surface of intersection. Using my time bubble power to take the stress out of final exams could get awkward if, when the bell rang, infinitely accelerated desk and carpet particles had burned a smoking circular hole in my surroundings (and possibly classmates).
Absent the physical concerns, however, during the Bush administration I often thought it would be fun to use such an ability to sneak into the White House at night and whisper “messages from God” in W.'s ear while he slept.
I’d probably be evil. And I’d be fun about it.
I’d find some dumbass running a 3-card monte game, and I’d stop time to put the red queen back in…and take all his money.
I’d bust Phil Hellmuth 4 players before the money…I’d give him 4 kings and some no-name schmuck 4 aces.
I would be a star goalie, play in the NHL, I’d have a goals against average of .50, I’d let a few in so they didn’t think I was cheating. Of course, no goals against me by Cindy Crosby or ANY of the Bruins!
While I was out there, I’d tie Sean Avery’s skates together. Then I’d put his skate guards back on to watch him fall too.
I’d go into a high school and find the snobby girl who picks on the nerdy boys, and I’d drop her panties while she was giving a book report.
I would go to my ex-wife’s house and leave a pair of tighty-whities in her pocketbook, with it open. (She did something similar to me, left a pair of her panties next to my bed when she picked up my daughter while I was at work…pissed off my girlfriend big time!)
I would go to the IRS office and format all their computers, steal all their pens, short-sheet their beds, and glue their butt cheeks together.
Just for good measure, I’d stop time when we knew where Osama bin Laden was, go get him, duct tape him and put him on the White House lawn.
I hate to say it, but I would steal, live well, and never have to work again.
I’ve thought and thought about it, and know it’s wrong, but there it is.
More mundane, but I’d use it to check the cards/stack the deck while gambling in a casino. Straight flush at three card poker, betting table maximum, 40-1 payout.
In my younger days, I’d probably have overindulged in avoidance behavior: Use it to get out of doing some unpleasant task. Thus, I’d probably have gotten psychologically stuck inside the stopped time, and never been willing to come out.
Now I’d sleep.
I’ve always wanted to do this too. Usually it was to get a paper done or some other task because I was such a procrastinator. And right up there with that was walking into the bank and grabbing a whole lot of money. Wow, you guys worried about the physics of it? What would you breathe? Air, of course. Air only for you. I also thought it would be fun if you could stop time with one other person so you could have fun together while everyone else was frozen. I’m impressed with the ideas to do all sorts of good. I honestly never thought about that before…
Break Vegas, then Break the World!
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I haven’t been a closeted gay teen for about 45 years, but that fantasy never dies. 
I would also become very famous for capturing Osama bin Laden, and hauling his ass (no, not his donkey) back to my own personal dungeon.
If I could stop time?
I’d
I’d cheat at Monopoly.
As a new parent the first thing that came to mind: sleep. Oh dear God, I want to sleep…
If I had the energy and resources to commit some proper hijinks, well…Sean Hannity’s show would get a lot more interesting.
Charter Memberships for everyone!
Of course rather than breaking into the Chicago Reader’s web host and making the changes that way, I’d get the money to pay for the members’ accounts. I’d do this by stealing from James Hoffa, because I hate him. And as long as I were at it, I’d pants him, too.
Oh, yeah, I’d still have to break in in order to do the “charter” part.
Really, all you can do is look. Your experience would be something like strolling through a sculpture garden.
Imagine if you did try to move bodies. You would have to move something from* here* to there in no time. You would destroy it.
I speak from experience. 
Why do I have a mental picture of someone in stopped or slowed time touching someone’s arm and breaking it? From some movie or comic book or manga or something… Or maybe just an amalgam of a bunch of things.
I wouldn’t do anything evil or destructive other than to get even with my enemies and sabotaging their lives. The possibilities here are endless.
If I knew the bank’s security camera wouldn’t even be able to capture one single frame of my presence I’d have myself a good run at all the free money (okay, maybe that’s evil, but still…)
If I knew my time was infinite I’d go see all the places I’ve wanted to see. I just hope any pictures I took would come with me once time resumed. I suppose I could shoot video, but it would look strange seeing the whole world stuck in pause mode, and I’m not even sure if a video camera would be capable of capturing what I see as a moment of time stopped.
I’d use this extra time to get caught up on all the things I don’t have time to do now.
I’d also probably develop carpal tunnel syndrome.
But if time is stopped, how would you travel? It’s not like planes are going to move, and even if your car does, you’d have to get around all the other frozen traffic, pedestrians, etc.
Yea, actually, even if we assume anything that is a part of you is not affected, every air molecule on the surface of your skin would refuse to budge, for pretty much the reason Boyo Jim stated.
That’s a lot of… typing you’re catching up on. 
There are these amazing devices: they’re called legs.