Without a second thought, I would choose seeing the future over changing my past.
Why?
I don't regret anything in my past, it all happened for a reason.
With the AMAZING power of seeing into the future, I could keep everyone of my family and friends safe. I would see every accident or hurtful situation, which would help me stop it, or prepare for the consequences. Although, at the same time I would see when everyone would eventually die - this is quite depressing.
This would also benefit me for my work shifts. If there was a day I know I wouldn't feel like working, I could call in sick in advance! >=)
Wait, would this also mean that I could see the new fashion trends? Then I can pretend that I "started" them. ;) Wicked.
On the other hand - I would really hate to deal with the cons of this power.
The future is subjective, always changing. What if it changed so quickly that I didn't see it and I wasn't prepared? What if while trying to prevent the situation when it arrives, I do something wrong, and it triggers a newly developed future? Finally, what if I can't stop the horrible thing from coming, and I have to watch a loved one suffer knowing that this is just the way it has to be?
I must admit, having this power would be pretty interesting.. However, I don't think I could deal with any of these outcomes. I think I much rather prefer living normally instead of living with the future stored at the back of my head. All in all, I'd have to call this a curse instead of a gift.