I agree with many posts above on stating that the concept of time travel has been portrayed in a very unrealistic manner in most literature and hollywood films. Time travel and the idea of manipulating time are still very controversial and debatable subjects. Despite the fast progress in development of technology in our current society, time travel comes with more complications and aftermath. 

Post #8 is right.  Hollywood and literature in general have not exactly been very supportive of the whole time travel issue.  The premise of it always seems glamorous and amazing at first (Delorean, anybody?), but it consistently turns out terrible and horrifying in the end.  I can make a much longer list for books and movies about time travel gone wrong, than I could for a 'pro time travel' story. 

I love #7s idea on time travel. There are many things which are too big for us to understand. That said, I do believe time travel to be impossible. With the advancement of technology, I would think that something (by this point) would have been discovered by now. I do have to say that I am happy that it has not been completed. Remembering all of the movies depicting time travel has put a sort of fear in me regarding it (the whole altering of the future thing).

I agree with post #6, that there is just so much about the universe that we cannot even begin to understand or fathom.  To our limited human perception, yes--it would seem as though time travel is an impossibility, but perhaps only because we cannot see the big picture.

We have created a framework for time based on the solar system we live in, the Earth's rotation and relationship to the Sun, and that is how most of us view time.  We organize our lives within that framework and mark the passing of time (birthdays, anniversaries) according to it.  Aside from that, we all live as long as we are going to, some more, some less than others, some work harder or longer hours and some never work at all.  So is time really all that relevant outside our desire to organize our lives and record events?

Is time travel possible?  Certainly, it's possible, although it might only be so outside humans ability to understand it, or in dimensions we are incapable of perceiving.  I would have to know everything about the universe to say it was impossible.

I like post 3's definition of time, especially since it nicely addresses the two connotations in which "time" needs to be considered. Time is a precious commodity, to be treasured and used wisely as much as possible, because we don't get it back once a given segment of it has gone by.

I don't think time travel is possible. It's fun to imagine in sci fi situations, but I don't think it's ever going to be an actual reality.

It hardly seems possible that time travel could ever actually happen.  For one thing, physics seems to preclude the idea of anything actually travelling faster than the speed of light.  This seems to imply that time travel would not be possible.  In addition, the paradoxes involved in time travel (could I do something in the past that would cause me not to be born, etc) are so complicated that they imply to me that time travel simply could not happen.

Time, to me, is two things. First, time is a context wherein events occur. Time is without depth or breadth in this view and is strictly, only, defined as the current moment of existence. 

Second, time is a concept of measurement used to chart the relationships between multiple events or relationships between discrete stages of single events. 

I'm probably leaving a lot undefined, but these are generally the two ways I see time.